No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Graphene-based rapid and highly-sensitive immunoassay for C-reactive protein using a smartphone-based colorimetric reader
Abstract
A novel immunoassay (IA) has been developed for human C-reactive protein (CRP), an important biomarker and tissue preserving factor for infection and inflammation. Graphene nanoplatelets (GNP) and 3-aminopropyltriethoxysilane (APTES) were admixed and covalently attached to a polystyrene based-microtiter plate (MTP), pretreated with KOH. The resulting surface served as a stable layer for the covalent attachment of the anti-human CRP antibody. The IA procedure was based on the one-step kinetics-based sandwich IA employing a minimum number of process steps, whereas the enzymatic reaction solution was monitored by a smartphone-based colorimetric reader. With a limit of detection and a limit of quantification of 0.07 ng mL−1 and 0.9 ng mL−1, it precisely detected CRP spiked in diluted human whole blood and plasma as well as the CRP levels in clinical plasma samples. The results obtained for “real-world” patient samples agreed well with those of the conventional immunosorbent assay and the clinically-accredited analyzer-based IA. The antibody-bound GNP-functionalized MTPs retained its original activity after 6 weeks of storage in 0.1 M PBS, pH 7.4 at 4 °C.
... In addition, the dynamic range and detection limits of the present fabricated CRP immunosensor were significantly improved in comparison to other recently developed CRP immunosensors reported in the literature, as shown in Table 2. The limit of detection in our case is higher than [16,[32][33][34][35][36], while lower than [37][38][39]. The detection range of the fabricated CRP immunosensor is lower than [32], but wider as compared to some other reported methods [16,[34][35][36][37][38][39]. ...
... The limit of detection in our case is higher than [16,[32][33][34][35][36], while lower than [37][38][39]. The detection range of the fabricated CRP immunosensor is lower than [32], but wider as compared to some other reported methods [16,[34][35][36][37][38][39]. However, the detection assay (a) is label-free, (b) lacks the Warburg diffusion limitation, which may arise from micro-structured fabricated electrodes, (c) has low-cost sample preparation, and (d) is a direct signal readout in the form of an electrical signal, which makes the present fabricated immunosensor advantageous than the reported methods [34][35][36][37][38]. ...
... The detection range of the fabricated CRP immunosensor is lower than [32], but wider as compared to some other reported methods [16,[34][35][36][37][38][39]. However, the detection assay (a) is label-free, (b) lacks the Warburg diffusion limitation, which may arise from micro-structured fabricated electrodes, (c) has low-cost sample preparation, and (d) is a direct signal readout in the form of an electrical signal, which makes the present fabricated immunosensor advantageous than the reported methods [34][35][36][37][38]. ...
An electrochemical capacitance immunosensor based on an interdigitated wave-shaped micro electrode array (IDWµE) for direct and label-free detection of C-reactive protein (CRP) was reported. A self-assembled monolayer (SAM) of dithiobis (succinimidyl propionate) (DTSP) was used to modify the electrode array for antibody immobilization. The SAM functionalized electrode array was characterized morphologically by atomic force microscopy (AFM) and energy dispersive X-ray spectroscopy (EDX). The nature of gold-sulfur interactions on SAM-treated electrode array was probed by X-ray photoelectron spectroscopy (XPS). The covalent linking of anti-CRP-antibodies onto the SAM modified electrode array was characterized morphologically through AFM, and electrochemically through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The application of phosphate-buffered saline (PBS) and human serum (HS) samples containing different concentrations of CRP in the electrode array caused changes in the electrode interfacial capacitance upon CRP binding. CRP concentrations in PBS and HS were determined quantitatively by measuring the change in capacitance (ΔC) through EIS. The electrode immobilized with anti-CRP-antibodies showed an increase in ΔC with the addition of CRP concentrations over a range of 0.01–10,000 ng mL−1. The electrode showed detection limits of 0.025 ng mL−1 and 0.23 ng mL−1 (S/N = 3) in PBS and HS, respectively. The biosensor showed a good reproducibility (relative standard deviation, (RSD) 1.70%), repeatability (RSD, 1.95%), and adequate selectivity in presence of interferents towards CRP detection. The sensor also exhibited a significant storage stability of 2 weeks at 4 °C in 1× PBS.
... In respect to sensitive biomarker quantitation, different approaches have been reported in the literature, including TiO 2 nanofibres treated with GPDES (3-glycidoxypropyl) methyldiethoxysilane (Fig. 1A); 80 inner glass capillary surfaces with ZnO nanorods modified with (3-glycidoxypropyl) trimethoxy silane (GPTS); 65 graphene nanosheets treated with 3-glycidyloxypropyl trimethoxysilane (GOPS); 54 glass slides silanised with epoxysilane surface 75,78 and functionalised graphene nanoplatelets with APTES (3-aminopropyl)triethoxysilane. 79 Silanisation and other surface modification chemistries also use aldehydes as cross-linkers for protein immobilisation. Some studies showed that amine derivatization followed by glutaraldehyde (GA) cross-linking yielded supports with greater amounts of immobilised enzymes and higher activity. ...
... The composition of BSA blocking solution used varies from 0.1 to 3% w/v, with incubation times that can go from seconds to several hours. 33,41,46,49,53,64,65,69,[72][73][74][79][80][81] This suggests that BSA has a broad capacity of surface passivation, which is independent of the surface chemistry and assay reagents. 110 CRP and CEA were quantified with LLoDs of 8 × 10 −4 and 4 × 10 −3 ng ml −1 in different microfluidic surfaces, such as TiO 2 fibres and glass. ...
... 73 CRP was quantified with a LLoD of 0.07 ng ml −1 (0.6 pM), also based on colorimetric enzymatic amplification and a smartphone camera. 79 The bio-barcode was able to quantify PSA using silver-enhanced gold nanoparticles, with a LLoD of 1.5 × 10 −5 ng ml −1 (5 × 10 −4 pM). 35 Although colorimetric detection has been used successfully for protein biomarker quantitation in microfluidic devices, fluorescence is by far the most common detection mode used for sensitive microfluidic immunoassays, as can also be seen in Table 1. ...
The latest clinical procedures for the timely and cost-effective diagnosis of chronic and acute clinical conditions, such as cardiovascular diseases, cancer, chronic respiratory diseases, diabetes or sepsis (i.e. the biggest causes of death worldwide), involve the quantitation of specific protein biomarkers released into the blood stream or other physiological fluids (e.g. urine or saliva). The clinical thresholds are usually in the femtomolar to picolomar range, and consequently the measurement of these protein biomarkers heavily relies on highly sophisticated, bulky and automated equipment in centralised pathology laboratories. The first microfluidic devices capable of measuring protein biomarkers in miniaturised immunoassays were presented nearly two decades ago and promised to revolutionise point-of-care (POC) testing by offering unmatched sensitivity and automation in a compact POC format; however, the development and adoption of microfluidic protein biomarker tests has fallen behind expectations. This review presents a detailed critical overview into the pipeline of microfluidic devices developed in the period 2005-2016 capable of measuring protein biomarkers from the pM to fM range in formats compatible with POC testing, with a particular focus on the use of affordable microfluidic materials and compact low-cost signal interrogation. The integration of these two important features (essential unique selling points for the successful microfluidic diagnostic products) has been missed in previous review articles and explain the poor adoption of microfluidic technologies in this field. Most current miniaturised devices compromise either on the affordability, compactness and/or performance of the test, making current tests unsuitable for the POC measurement of protein biomarkers. Seven core technical areas, including (i) the selected strategy for antibody immobilisation, (ii) the surface area and surface-area-to-volume ratio, (iii) surface passivation, (iv) the biological matrix interference, (v) fluid control, (vi) the signal detection modes and (vii) the affordability of the manufacturing process and detection system, were identified as the key to the effective development of a sensitive and affordable microfluidic protein biomarker POC test.
... Nowadays, there is growing in smartphones usage in medical field. Smartphone has been involved and used in clinical application, such as, colorimetric imaging [1][2][3][4][5]. The important reason for that is the skyrocketing that happened in nanotechnology, which allow the specialist to integrate biosensors and bioelectronics with these smartphones. ...
... One form for "Smart phones: new clinical tools in oncology" [10] p. 429 is the review centric research approach in which a researcher reviews "The use of smartphone applications by urology trainees" [6] p. 263, but the argument can be that also our knowledge still do not have enough technologies. In the research offered here the focus is on joining the most important "Using smartphone in health field " [2]. In this study I recognize the most vital cell phones uses in the medicinal field that help with the present business or progressive situation to fabricate our goal to accomplish a high ground. ...
... Smartphones can quantify the concentration of analytes by picking up changes in the color "space" of the test strip. Prior to this, these color "spaces" would have been explored and calibrated, including intensity of red/green/blue (RGB) (Vashist et al., 2015a;Soga et al., 2013;Vashist et al., 2015b) biomarkers. They demonstrated a portable device, a smartcard, which monitors cholesterol levels in the blood using a smartphone. ...
... Another smartphone-based colorimetric reader (SBCR) device (Vashist et al. 2015a(Vashist et al. , 2015bVenkatesh et al., 2017), was developed and applied to, for example, the immunoassay of human C-reactive protein (CRP) (Comina et al., 2016). The device had a darkroom inside the reader support frame made of polyamide. ...
The emergence of the smartphones has brought extensive changes to our lifestyles, from communicating with one another, to shopping and enjoyment of entertainment, and from studying to functioning at the workplace (and in the field). At the same time, this portable device has also provided new possibilities in scientific research and applications. Based on the growing awareness of good health management, researchers have coupled health monitoring to smartphone sensing technologies. Along the way, there have been developed a variety of smartphone-based optical detection platforms for analyzing biological samples, including standalone smartphone units and integrated smartphone sensing systems. In this review, we outline the applications of smartphone-based optical sensors for biosamples. These applications focus mainly on three aspects: Microscopic imaging sensing, colorimetric sensing and luminescence sensing. We also discuss briefly some limitations of the current state of smartphone-based spectroscopy and present prospects of the future applicability of smartphone sensors.
... Aptamer based-sandwich assay can potentially fulfill the growing requirements for such a diagnostic assay. Experiments with aptamers in lateral flow devices and disposable biosensors have showed the reliability and stability of the assay with patient serum whole blood (48, [70][71]. Advantages of The POCT test includes: simple to manipulate, easy to handle and capable of rapid data processing in a single device even when used by an untrained personnel (71)(72)(73). ...
... Experiments with aptamers in lateral flow devices and disposable biosensors have showed the reliability and stability of the assay with patient serum whole blood (48, [70][71]. Advantages of The POCT test includes: simple to manipulate, easy to handle and capable of rapid data processing in a single device even when used by an untrained personnel (71)(72)(73). The developed assay platform provides a simple and rapid method for detecting TK1 in a serial order. ...
Thymidine kinase 1 (TK1) is traditionally a serum biomarker that is elevated in the early stages of malignancies. The diagnostic and prognostic role of TK1 for screening and monitoring human malignancies has recently been investigated. Anti-human TK1 aptamers were selected through 12 iterative rounds of systematic evolution of ligands by exponential enrichment from a DNA library. The aptamer pool of round 12 was amplified, and the polymerase chain reaction product was cloned on the TA vector. Of the 85 colonies obtained, 52 were identified as positive clones. These aptamers were screened for TK1 with surface plasmon resonance, where apta37 and apta69 showed the highest affinity for TK1. The TK1_apta37 and TK1_apta69 aptamers were used in a sandwich assay platform and successfully detected TK1 in the concentration range of 54-3500 pg mL-1. Clinical samples from 60 cancerous patients were also tested with this assay system and compared using the conventional antibody-based enzyme-linked immunosorbent assay kit. The aptamer sandwich assay demonstrated a dynamic range for TK1 at clinically relevant serum levels, covering subpicogram per milliliter concentrations. The new approach offers a simple and robust method for detecting serum biomarkers that have low and moderate abundance. The results of this study demonstrate the screening capability of the aptamer sandwich assay platform and its potential applicability to the point-of-care testing system.
... Redrawn from ref. [33] conventional SPR, i.e., about 100-fold more sensitive [150]. Indeed, protein A was conjugated on a gold surface of an SPR sensing chip and then coupled with anti-CEA Ab for detecting purified CEA with a LOD of 0.5 ng.mL −1 [151], well below the normal level in blood. With the graphene modified Au chip, the sensitivity should be significantly lower as anticipated from the work of [151]. ...
... Indeed, protein A was conjugated on a gold surface of an SPR sensing chip and then coupled with anti-CEA Ab for detecting purified CEA with a LOD of 0.5 ng.mL −1 [151], well below the normal level in blood. With the graphene modified Au chip, the sensitivity should be significantly lower as anticipated from the work of [151]. However, it is a formidable task to fabricate a multi-channel SPR and the cost of this instrument including disposable Au sensing chips can be another issue for its acceptance in clinical and hospital settings. ...
This review (with 196 refs.) covers the state of the art in electrochemical and optical immunoassays for the carcinoembryonic antigen (CEA). In essence, it has sections on (a) frequently applied principles and types of CEA immunoassays; (b) aspects of sensor fabrication including immunological and immobilization procedures and the proper choice of nanomaterials; (c) electrochemical immunoassays, with subsections on assays based on the use of nanoparticles and other nanomaterials (such as conducting polymers and graphenes); (d) optical immunoassays based on the use of nanoparticles such as quantum dots, gold nanoparticles, upconversion nanoparticles, graphenes and their derivatives; (d) lateral flow and lab-on-a-chip (microfluidic) immunoassays; and (e) on multiplexed electrochemical and optical immunoassays with and without labels. Examples for applications to real samples are given. A final section discusses current limitations and trends in terms of sensing schemes and nanomaterials.
Graphical abstractA key to develop nanodevices with high performance for immunoassay applications is to explore advanced functional nanomaterials. This review focus on practical aspects trying to give the readers useful insights that should be considered such as the choice of the advanced nanomaterials to be used, the best methods/techniques in immunesensing of CEA.
... There are several reports in the literature with regard to the detection of CRP following different sensing approaches including enzyme immunoassays performed following standard procedures or more advanced approaches that improved the detection limit and reduced the assay time [36][37][38]. Since the scope of the present manuscript is not a literature review, a comparison only with the label-free approaches will be provided. ...
... Detection limit Dynamic range Assay duration Analysis of real samples Proposed sensor 2.1 ng/mL 5-100 ng/mL 5 min yes SPR [36] 1 μg/mL 1-26 μg/mL 10 min no SPR [37] 1 μg/mL 1-26 μg/mL 30 − 60 min no SPR [38] 20 ng/mL 20-100 ng/mL 2 min no SPR [39] 1.2 ng/mL 1.2-80 ng/mL 5 min yes LSPR [40] 100 pg/mL up to 100 μg/mL 30 min no LSPR+Interference [41] 1 fg/mL 1 fg/mL −100 μg/mL n.m. no RIfS [42] 55 ng/mL 0.044-2.9 μg/mL 30 min no RIfS [43] 100 ng/mL up to 10 μg/mL 20 min no RifS [17] 25 ng/mL 0.05-2.5 μg/mL 45 min yes Impendence [44] n.d.* 1 pg/mL−1 μg/mL 15 min limited EIS [45] 75 ng/mL up to 40 μg/mL n.m. no EIS [46] 32 ng/mL 80 ng/mL−1.6 μg/mL n.m. no Capacitance sensor [47] n.d.* 25 pg/mL−25 ng/mL 60 min no Electrochemical [48] 28 ng/mL 80 ng/mL−8 μg/mL 30 min yes Electrochemical [49] 11 ng/mL up to 5 μg/mL n.m. no Bragg grating [50] 10 ng/mL 0.01-100 μg/mL 10 min no of the immobilized antibody with the analyte in the samples was employed as the analytical signal. ...
An immunosensor for fast and accurate determination of C-reactive protein (CRP) in human serum samples based on an array of all-silicon broad-band Mach-Zehnder interferometers (BB-MZIs) is demonstrated. The detection was based on monitoring the spectral shifts during the binding of CRP on the antibody molecules that have been immobilized on the sensing arms of the BB-MZIs. By employing the reaction rate as the analytical signal the assay time was compressed to few minutes. The detection limit was 2.1 ng/mL, the quantification limit was 4.2 ng/mL and the linear dynamic range extended up to 100 ng/mL. The measurements performed in human serum samples with the developed immunosensor were characterized by high repeatability and accuracy as it was demonstrated by dilution linearity and recovery experiments. In addition, the concentration values determined were in excellent agreement with those determined for the same samples by a standard clinical laboratory method. The compact size of the chip makes the proposed immunosensor attractive for incorporation into miniaturized devices for the determination of clinical analytes at the point-of-need.
... A smartphone-based device is a promising platform for point-of-care (POC) applications with its proof of concept was introduced for detecting C-reactive protein (Vashist et al., 2015). Given the fact that nearly half of the world's population owns the smartphone, using smartphones in POC extends its potential applicability by enabling people to get self-testing of disease biomarkers at their convenient places. ...
Aptamers are an up-and-coming bioreceptor in application spanning from environmental monitoring to clinical diagnosis and therapeutic usage due to their relatively small size, chemical stability, easy modifications, and environmental compatibility over conventional bioreceptors. Together with the high demand for efficient biosensors, recent advances in nanobiotechnology have drawn many researchers’ keen attention to the development of innovative aptasensors that are performing rapidly and thoroughly with high sensitivity and selectivity to their target analytes.
In this review, overview of aptamer screening methodologies is briefly discussed, and then different types of aptamer-based biosensor platforms with their state-of-the-art applications are described. Several practical challenges on aptasensor development are also discussed to overcome their limited commercialization. Furthermore, perspectives on the promising future of aptasensors in application stretching across point-of-care technologies are addressed.
... Moreover, Vashist and colleagues developed an optical biosensor for CRP detection through a graphene-based immunoassay coupled to a smartphone-based colorimetric reader that led to CRP detection in clinical and diluted human whole blood samples, reaching a LOD of 0.07 ng/mL, without the interference of common proteins such as LCN2, HFA, HSA, IL-1β, IL-6, IL-8, and TNF-α [229]. A detailed description of relevant wearable-remote-portable biosensors assisted with GDMs is presented in Table 4. Abbreviations: Surface plasmon resonance (SPR); Fluorescence resonance energy transfer (FRET); Graphene Enhanced Raman Spectroscopy (GERS); Fluorophore carboxyfluorescein (FAM); Cardiac troponin I (cTnI); B-type natriuretic peptide (BNP); 5 -6-FAM-modified anti-cTnI aptamers (FMAA); Double-stranded and dual-anchored fluorescent aptamer on rGO nanosheets (DAGO); Chemiluminescent (CL); Chicken interleukin-4 (ChIL-4); Nitrogen-doped graphene (NG); Horseradish peroxidase (HRP). ...
Chronic inflammatory diseases, such as cancer, diabetes mellitus, stroke, ischemic heart diseases, neurodegenerative conditions, and COVID-19 have had a high number of deaths worldwide in recent years. The accurate detection of the biomarkers for chronic inflammatory diseases can significantly improve diagnosis, as well as therapy and clinical care in patients. Graphene derivative materials (GDMs), such as pristine graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO), have shown tremendous benefits for biosensing and in the development of novel biosensor devices. GDMs exhibit excellent chemical, electrical and mechanical properties, good biocompatibility, and the facility of surface modification for biomolecular recognition, opening new opportunities for simple, accurate, and sensitive detection of biomarkers. This review shows the recent advances, properties, and potentialities of GDMs for developing robust biosensors. We show the main electrochemical and optical-sensing methods based on GDMs, as well as their design and manufacture in order to integrate them into robust, wearable, remote, and smart biosensors devices. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers with improved sensitivity, reaching limits of detection from the nano to atto range concentration.
... Graphene can be functionalized based on the adsorption capacity of graphene to protein and nucleic acids to obtain a higher specificity of graphene-based materials. By means of KOH pretreatment, Vashist and colleagues covalently linked a graphene nano-platelet (GNP) to a polystyrene microtitration plate (MTP) using silane coupling agent APTES to synthesize a colorimetric sensing platform rich in human C-reactive protein (CRP) antibodies [55]. As shown in Figure 2a, the analytical sample is dripped onto GNP/MTP, and after incubation at 37 °C for 15 min, CPR binds with antibodies to make GNP/MTP have catalytic oxidation activity, resulting in a significant color change in TMB. ...
Two-dimensional (2D) materials such as graphene, graphene oxide, transition metal oxide, MXene and others have shown high potential for the design and fabrication of various sensors and biosensors due to their 2D layered structure and unique properties. Compared to traditional fluorescent, electrochemical, and electrical biosensors, colorimetric biosensors exhibit several advantages including naked-eye determination, low cost, quick response, and easy fabrication. In this review, we present recent advances in the design, fabrication, and applications of 2D material-based high-performance colorimetric biosensors. Potential colorimetric sensing mechanisms and optimal material selection as well as sensor fabrication are introduced in brief. In addition, colorimetric biosensors based on different 2D materials such as graphene, transition metal dichalcogenide/oxide, MXenes, metal–organic frameworks, and metal nanoplates for the sensitive detection of DNA, proteins, viruses, small molecules, metallic ions, and others are presented and discussed in detail. This work will be helpful for readers to understand the knowledge of 2D material modification, nanozymes, and the synthesis of hybrid materials; meanwhile, it could be valuable to promote the design, fabrication, and applications of 2D material-based sensors and biosensors in quick bioanalysis and disease diagnostics.
... For example, Vashist et al. demonstrated the reading of a colorimetric 96-well-plate assay for C-reactive protein (a biomarker of inflammation) using a large dark box and two smart devices: one underneath the plate (an iPad, iPad mini, or iPhone 5s) with a white screensaver to provide uniform transmitted illumination and a smartphone with camera at the top of the box to image the transmitted light [86]. The assay was analyzed with three different phones (Samsung Galaxy S3 mini, iPhone 4, and iPhone 5s), giving similar results for all with LODs of ca. 1 ng mL −1 in plasma and whole blood [50]. ...
This chapter focuses on optical smartphone platforms that are under development and have potential to impact clinical medicine. It aims to revisit how a smartphone camera can be used for optical measurements, including spectroscopy, and how the use of peripherals enables the creation of spectroscopic devices that can measure clinical samples. Smartphone-based imaging systems and spectrometers utilize the camera chip of the smartphone as an optical detector for measurements of light intensity and color. The chapter discusses types of clinical samples, the biomarker content to be analyzed by smartphone spectroscopy and imaging. The distinct advantage to creating a smartphone imaging or spectrometric analysis platform is portability and reduction in instrumentation cost. Smartphone microscopy has been developed, with many commercial devices now available for bright-field imaging. Smartphone cameras can be readily manipulated to read and even perform complete clinical assays for a wide variety of biomarkers in multiple different formats, in both resource-limited and near-patient settings.
... LODs of other biosensors were better than those of our report. ELISA (Vashist et al., 2015) and paper-based microfluidic assay (Dong et al., 2017) required multi operation steps, then lateral flow immunoassay (Cai et al., 2018) needed complicated Paper-Based Microfluidic Immunoassay Up to 2 µg mL −1 54 ng mL −1 Multi-step Dong et al., 2017 Homogeneous immunoassay 2.5-10 µg mL −1 2.5 µg mL −1 Single-step Our method device fabrication. Electroosmotic lateral flow immunoassay (Oyama et al., 2012) also required multi operation steps and electrophoretic separation of complexes and free forms. ...
In this study, we report an inkjet printing-based method for the immobilization of different reactive analytical reagents on a single microchannel for a single-step and homogeneous solution-based competitive immunoassay. The immunoassay microdevice is composed of a poly(dimethylsiloxane) microchannel that is patterned using inkjet printing by two types of reactive reagents as dissolvable spots, namely, antibody-immobilized graphene oxide and a fluorescently labeled antigen. Since nanoliter-sized droplets of the reagents could be accurately and position-selectively spotted on the microchannel, different reactive reagents were simultaneously immobilized onto the same microchannel, which was difficult to achieve in previously reported capillary-based single-step bioassay devices. In the present study, the positions of the reagent spots and amount of reagent matrix were investigated to demonstrate the stable and reproducible immobilization and a uniform dissolution. Finally, a preliminary application to a single-step immunoassay of C-reactive protein was demonstrated as a proof of concept.
... Apparently, the detection limit of this approach for H 2 S is well above 50 μM but lower 100 μM if the color development is simply visualized and compared with a predetermined score chart. The detection sensitivity, however, can be greatly improved by using a commercial test strip reader, a hand-held colorimeter or even a smartphone [42] to quantify the color intensity. ...
Silver-doped CdS quantum dots capped with mercaptoacetic acid (CdSAg-MAA QDs) were prepared and are shown to be a quenchable fluorescent probe for hydrogen sulfide (H2S). The optimized approach exhibits a linear response in the 0.01 to 500 μM H2S concentration range and a 3.0 nM detection limit (RSD = 0.54 % for n = 5 at 10 nM of H2S). The estimated endogenous H2S levels in local wastewater were 45.4 μM and 48.7 μM and the assays were not responsive to various ions often present in water and wastewater. The method gave recoveries ranging from 98 to 102 % for the analysis of acidified wastewater spiked with H2S. Consequently, a simple colorimetric test strip was prepared by impregnating the filter paper with a mixture of CdSAg-MAA QDs and chitosan. The test strip exhibited good selectivity and sensitivity for the quantitation of H2S in local wastewater samples.
Graphical AbstractA simple, sensitive and selective silver-doped CdS quantum dot fluorescent probe for H2S in real sample is presented. To evaluate their practical applicability, test stripes for H2S were prepared and exhibited good selectivity for H2S.
... The current literature in the context of smartphone-based biomarker detection leads in lateral flow assays [34], microarray chips [25], μwellbased methods [35][36][37] and electrochemical techniques [38]. A few studies show that a more practical approach is possible using spot-like modules on paper for the analysis [10,39,40]. ...
The need for a continuous, real-time monitoring of specific diseases represents an unmet scientific need. Evidently, cancer is one of the most important diseases where it is crucial to increase the rates of patient survival and monitor disease prognosis. Herein, a novel type of immunoassay was developed for detection of cancer biomarkers, using alpha-fetoprotein (AFP) and mucin-16 (MUC16) as model analytes. Using gold nanoparticle (AuNP) bioconjugates as a signal production tool, relevant antibody (Ab)-conjugated AuNPs were prepared on the nitrocellulose (NC) membrane. To construct a spot-like point-of-care (POC) immunoassay, cysteamine conjugated AuNPs (AuNP-Cys) were immobilized on the NC membrane and antibodies were conjugated to the nanoparticle on the detection pad, following a treatment with the samples that contains AFP or MUC16 which are well-known protein biomarkers for liver and ovarian cancer. By using the change in the colorimetric properties of AuNPs, detection of tumor markers was achieved by using a smartphone image and color analysis software at the final stage. Image J application was used for the evaluation of color changes depending on the biomarker concentration in buffer or spiked synthetic serum samples. The linear range was found as 0.1 ng/mL-100 ng/mL for AFP and 0.1–10 ng/mL for MUC16. Limit-of-detection (LOD) was calculated as 1.054 ng/mL and 0.413 ng/mL for AFP and MUC16, respectively. Interferent molecules, Her2, Immunoglobulin G (IgG) and bovine serum albumin (BSA) were tested on the system. Furthermore, synthetic serum samples spiked with selected analyte molecule were applied on the system and measured successfully.
... Hence, microprism or optical fiber arrays were employed to solve these problems [22], but thus the sensor development lacks of simplicity. When enlarging the shooting distance [23] and capturing the "before" and "after" images of the array in the same experimental conditions, the picture can be taken at a suitable distance without optical aberrations. Some smartphone-based devices are commercial available for point of care testing of various analytes using sweat, saliva and blood [24]; as techniques and costly reagents, the cost for each analysis is expansive. ...
In this work, we present a smartphone-based multiplexed enzymatic biosensor utilizing the unique colorimetric properties of the poly(aniline-co-anthranilic acid) (ANI-co-AA) composite film coupled with horseradish peroxidase (HRP), glucose oxidase (GOx), horseradish peroxidase-glucose oxidase (GOx-HRP) and tyrosinase (Tyr) enzymes. The enzymes are immobilized on the composite polymer film by adsorption and they catalyze a reversible redox color change of the host polymer from green to blue in the presence of their substrate. A smartphone was applied as color detector, for image acquisition and data handling. A ColorLab® android application, free of charge software application, was used to enable easy and clear display of the sensors' response indicating remarkable changes in the optical features. The results were confirmed by the spectrophotometric measurements. The developed colorimetric enzymatic biosensors were studied and optimized in relation to different experimental parameters. Moreover, the colorimetric enzymatic biosensors were applied to food and pharmaceutical analysis. It has been shown by these studies that the colorimetric biosensors are promising as quick and simple tests for handheld analysis in various fields.
... Many different methods and materials have been proposed, in order to tackle the ASSURED criteria bottleneck. Lateral flow assays [25][26][27][28][29] and smartphone-based [30] colorimetric [31][32][33] and electrochemical [34][35][36] PoC devices are only few, indicative examples of the vast work been done so far towards PoC testing devices that can reduce detection time, increase detection accuracy and ultimately reduce overall cost. Lab-on-PCB (LoPCB) is an alternative approach to PoC diagnostic systems that could reduce the costs associated with complex detection architectures [37][38][39][40][41][42][43][44]. ...
Point of Care (PoC) diagnostics have been the subject of considerable research over the last few decades driven by the pressure to detect diseases quickly and effectively and reduce healthcare costs. Herein, we demonstrate a novel, fully integrated, microfluidic amperometric enzyme-linked immunosorbent assay (ELISA) prototype using a commercial interferon gamma release assay (IGRA) as a model antibody binding system. Microfluidic assay chemistry was engineered to take place on Au-plated electrodes within an assay cell on a printed circuit board (PCB)-based biosensor system. The assay cell is linked to an electrochemical reporter cell comprising microfluidic architecture, Au working and counter electrodes and a Ag/AgCl reference electrode, all manufactured exclusively via standard commercial PCB fabrication processes. Assay chemistry has been optimised for microfluidic diffusion kinetics to function under continual flow. We characterised the electrode integrity of the developed platforms with reference to biological sampling and buffer composition and subsequently we demonstrated concentration-dependent measurements of H2O2 depletion as resolved by existing FDA-validated ELISA kits. Finally, we validated the assay technology in both buffer and serum and demonstrate limits of detection comparable to high-end commercial systems with the addition of full microfluidic assay architecture capable of returning diagnostic analyses in approximately eight minutes.
... As can be seen in figure 6, the antibody molecule consists of two identical β-sheet polypeptide chains (Fab fragments) supporting antigen binding, and one Fc domain. The Fc region is the stem of the 'Y'-shaped antibody molecule with a carboxyl end, while the Fab domains consist of amine group at the terminal [38,[44][45][46][48][49][50][51]. To obtain the oriented immobilization, the primary antibody molecules were connected to NH-functionalized IDEs through their Fc carboxyl terminals, which were activated via EDC ( figure 6) [51]. ...
Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein a novel type of highly sensitive, compact and portable immunosensor based on gold interdigital capacitor has been designed and developed for rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl and were immobilized on amino-terminated SAM for better control of oriented immobilization of antibody on gold IDEs. In addition, gold nanoparticles conjugated with secondary antibody were used to enhance the sensitivity. Under the optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg/mL, the linear range from 5 pg/mL to 1 ng/mL and the detection limit of 1.34 pg/mL, at signal/noise ratio of 3.
... This chapter describes an extremely low-cost SBCR (Figs. 1 and 2) that employs a commercial gadget (iPAD mini, iPAD4, or iPhones 5s), an inexpensive polyamide dark hood and a polyamide base holder [5]. It serves as the colorimetric readout of graphenebased CRP IA [6] (Fig. 3) and compared with commercial MTPR for its analytical performance. As an important biomarker for infection and inflammation [7], CRP analysis is needed for a wide range of diseases, disorders, and pathophysiological conditions, such as neonatal sepsis [8][9][10][11][12], inflammasome related diseases [13], depressive and posttraumatic stress [14][15][16], diabetes [17][18][19], and cardiovascular diseases [20][21][22][23][24]. ...
A smartphone-based colorimetric reader (SBCR), comprising a Samsung Galaxy SIII mini, a gadget (iPAD mini, iPAD4, or iPhone 5s) and a custom-made dark hood and base holder assembly, is used for human C-reactive protein (CRP) immunoassay. A 96-well microtiter plate (MTP) is positioned on the gadget’s screensaver to provide white light-based bottom illumination only in the specific regions corresponding to the well’s bottom. The images captured by the smartphone’s back camera are analyzed by a novel image processing algorithm. Based on one-step kinetics-based human C-reactive protein immunoassay (IA), SBCR is evaluated and compared with a commercial MTP reader (MTPR). For analysis of CRP spiked in diluted human whole blood and plasma as well as CRP in clinical plasma samples, SBCR exhibits the same precision, dynamic range, detection limit, and sensitivity as MTPR for the developed IA (DIA). Considering its compactness, low cost, advanced features and a remarkable computing power, SBCR is an ideal point-of-care (POC) colorimetric detection device for the next-generation of cost-effective POC testing (POCT).
... Therefore, a high-sensitivity CRP (hs-CRP) detection under the clinically relevant CRP concentration range (0-5 g/mL), including a clinical cutoff concentration (1 and 3 g/mL), is highly desirable to predict the risk of cardiovascular disease. Many approaches for hs- CRP detection have been developed, including the commercialized methods [4,5], the microfluidic systems [6,7], and other compli- cated methods [8,9]. ...
Although vertical flow assays (VFAs) have a number of advantages compared to lateral flow assays (LFAs) such as a short analysis time, no line interference, and no Hook effect, VFAs are not preferred as LFAs because of their complicated operation principle. In this study, we demonstrated VFAs with multistep reactions for the detection of C-reactive protein (CRP) based on the programmed reagent loading in a pressed region integrated 3D paper-based microfluidic device. The flow order of all reagents in a 3D paper-based microfluidic device was programmed based on the delayed flow caused by the pressed region as well as the geometry modification of the paper channel. After simultaneous loading of all the reagents required for assays, they are sequentially loaded into the analysis region with a programmed sequence. As a proof of concept, a high-sensitivity CRP (hs-CRP) detection with signal amplification was performed to predict the riskiness of cardiovascular disease within 15 min. The detection limit was improved from 0.01 to 0.005 μg/mL via a maximum 3.47-fold signal amplification. Additionally, the upper limit of hs-CRP detection was increased to 5 μg/mL without Hook effect. Finally, we successfully detected hs-CRP in a clinically relevant range (0.005–5 μg/mL), while LFAs cannot cover due to the Hook effect.
... [83] A great number of these systems rely on smartphone-integrated peripherals, most often their camera [84] (figure 1.2.3). Colorimetric detection-based systems have been utilized for applications ranging from the monitoring of pH level in sweat [85], chlorine concentrations in water [86] or C-reactive protein levels in blood [87]. Cell counting was also demonstrated using that same principle [88]. ...
Recent developments in the life-science -omics disciplines, together with advances in micro and nanoscale technologies offer unprecedented opportunities to tackle some of the major healthcare challenges of our time. Lab-on-Chip technologies coupled with smart-devices in particular, constitute key enablers for the decentralization of many in-vitro medical diagnostics applications to the point-of-care, supporting the advent of a preventive and personalized medicine.
Although the technical feasibility and the potential of Lab-on-Chip/smart-device systems is repeatedly demonstrated, direct-to-consumer applications remain scarce. This thesis addresses this limitation. System evolvability is a key enabler to the adoption and long-lasting success of next generation point-of-care systems by favoring the integration of new technologies, streamlining the reengineering efforts for system upgrades and limiting the risk of premature system obsolescence. Among possible implementation strategies, platform-based design stands as a particularly suitable entry point. One necessary condition, is for change-absorbing and change-enabling mechanisms to be incorporated in the platform architecture at initial design-time. Important considerations arise as to where in Lab-on-Chip/smart-device platforms can these mechanisms be integrated, and how to implement them.
Our investigation revolves around the silicon-nanowire biological field effect transistor, a promising biosensing technology for the detection of biological analytes at ultra low concentrations. We discuss extensively the sensitivity and instrumentation requirements
set by the technology before we present the design and implementation of an evolvable smartphone-based platform capable of interfacing lab-on-chips embedding such sensors. We elaborate on the implementation of various architectural patterns throughout the platform and present how these facilitated the evolution of the system towards one accommodating for electrochemical sensing. Model-based development was undertaken throughout the engineering process. A formal SysML system model fed our evolvability assessment process. We introduce, in particular, a model-based methodology enabling the evaluation of modular scalability: the ability of a system to scale the current value of one of its specification by successively reengineering targeted system modules.
The research work presented in this thesis provides a roadmap for the development of evolvable point-of-care systems, including those targeting direct-to-consumer applications. It extends from the early identification of anticipated change, to the assessment of the ability of a system to accommodate for these changes. Our research should thus interest industrials eager not only to disrupt, but also to last in a shifting socio-technical paradigm.
... Colorimetric, chemiluminometric, or fluorometric signals produced from the biosensor cartridge may be detected http using the built-in camera in the phone. However, the image quality is difficult to maintain in a reproducible manner due to various users holding different models of smartphone [14,15]. Such variation causes re-alignment of the object to the camera lens because each model adopts a unique design with different arrangement of parts. ...
Healthcare via internet-of-things (IoT) for protection against consumption of contaminated foods was demonstrated via immuno-analysis of pathogenic bacteria and the sharing of results using a mobile device. As wireless internet has spread widely over the world, it can be readily used to communicate information related to, for example, human health. Indeed, some institutes have demonstrated the measurement of physical vital signals (e.g., temperature, pulse, and heartbeat) of the body for monitoring through a smartphone. However, biochemical analytes such as proteins and bacteria are currently difficult to measure based on antigen-antibody binding due to several technological barriers. Among them, the terminal unit of detection for, for instance, pathogens is mostly bulky, insensitive, or even expensive for sophisticated devices. We have studied the use of CMOS image sensor (CIS) for detecting the signal produced from an immuno-analytical system, which could resolve the detection issue hindering monitoring via IoT. In this study, an immunosensor system using CIS for detection means was fabricated to pocket-sized dimensions and then employed for determining a food-borne pathogen, the Vibrio species, in real samples. The analysis was controlled and monitored using a smartphone that was also used to upload the result as data to the internet server for sharing with the public. To our knowledge, this study could be the first exemplification of pathogen monitoring via IoT in the field of healthcare.
The concept of plasmonic MEMS and micropatterning have been developed for various applications including compact chemical and biological sensors, optical data storage, micro/nano imaging, and ultrahigh resolution displayers and printers, to name a few. Subwavelength confinement and enhancement of light by surface plasmons make it possible to build ultra-sensitive biological imaging and sensing devices and integrate them in a wide range of different on-chip applications. Here we focus on the emerging field of bio-sensing and bio-imaging, including refractive-index based label-free biosensing; plasmonic near-field scanning optical microscopy; plasmonic integrated lab-on-chip for point-of-care (POC) systems; and plasmonic on-chip cellular imaging.
The development of novel biomedical sensors as highly promising devices/tools in early diagnosis and therapy monitoring of many diseases and disorders has recently witnessed unprecedented growth; more and faster than ever. Nonetheless, on the eve of Industry 5.0 and by learning from defects of current sensors in smart diagnostics of pandemics, there is still a long way to go to achieve the ideal biomedical sensors capable of meeting the growing needs and expectations for smart biomedical/diagnostic sensing through eHealth systems. Herein, an overview is provided to highlight the importance and necessity of an inevitable transition in the era of digital health/Healthcare 4.0 towards smart biomedical/diagnostic sensing and how to approach it via new digital technologies including Internet of Things (IoT), artificial intelligence, IoT gateways (smartphones, readers), etc. This review will bring together the different types of smartphone/reader-based biomedical sensors, which have been employing for a wide variety of optical/electrical/electrochemical biosensing applications and paving the way for future eHealth diagnostic devices by moving towards smart biomedical sensing. Here, alongside highlighting the characteristics/criteria that should be met by the developed sensors towards smart biomedical sensing, the challenging issues ahead are delineated along with a comprehensive outlook on this extremely necessary field.
Advancement of materials along with their fascinating properties play increasingly important role facilitating the rapid progress in medicine. An excellent example is the recent development of biosensors based on nanomaterials that induces surface plasmon effect for screening biomarkers of various diseases ranging from cancer to Covid-19. The recent global pandemics re-confirmed a trend of real-time diagnosis in public health to be in point-of-care (POC) settings that can screen interested biomarkers at home, or literally anywhere else, at any time. Plasmonic biosensors, thanks to its versatile designs and extraordinary sensitivities, can be scaled into small and portable device for POC diagnostic tools. In the meantime, efforts are being made to speed up, simplify and lower the cost of the signal readout process including converting the conventional heavy laboratory instruments into handheld devices. This article reviews the recent progress on the design of plasmonic nanomaterial-based biosensors for biomarker detection with a perspective of POC applications. After briefly introducing the plasmonic detection working mechanisms and devices, the selected highlights in the field focusing on the technology's design including nanomaterials development, structure assembly, and target applications are presented and analyzed. In parallel, discussions on the sensor's current or potential applicability in POC diagnosis are provided. Finally, challenges and opportunities in plasmonic biosensor for biomarker detection, such as the current Covid-19 pandemic and its test using plasmonic biosensor and incorporation of machine learning algorithms are discussed.
Microfluidic immunoassay devices are a promising technology that can quickly detect biomarkers with high sensitivity. Recently, many studies implementing this technology on paper substrates have been proposed for improving cost and user-friendliness. However, these studies have identified problems with the large volume of sample required, low sensitivity, and a lack of quantitative accuracy and precision. In this paper, we report a novel structure implemented as a cellulosic material-based microchannel device capable of quantitative immunoassay using small sample volumes. We fabricated microfluidic channels between a transparent cellophane film and water-resistant paper to facilitate loading of small-volume samples and reagents, with a 40-μm-wide immunoreaction matrix constructed in the center of the microchannel using highly precise photolithography. A fluorescence sandwich immunoassay for C-reactive protein (CRP) was successfully implemented that required only a 1-μL sample volume and a 20-min reaction time. We confirmed that the limit of detection of the device was 10-20 ng/mL with a coefficient of variation under 5.6%, which is a performance level comparable to conventional plastic-based human CRP enzyme-linked immunosorbent assay (ELISA) kits. We expect that such devices will lead to the elimination of large amounts of medical waste from the use of ubiquitous diagnostics, a result that is consistent with environmental sustainability goals.
A new method of SPR signal amplification based on dynamic field enhancement at the sensor surface to detect C-reactive protein (CRP) is proposed. The gold nanoparticles-detection antibody (AuNPs-dAb) conjugates, as the dynamical agent, were applied to enhance the biosensor sensitivity. The mechanism of SPR sensitivity enhancement is due to the strong evanescent field coupling between the localized SPR (LSPR) of AuNPs and SPR of gold-silver alloy film which proved by COMSOL Multiphysics and MATLAB simulation. The biosensor sensitivity got with sandwich immunoassay (cAb/CRP/AuNPs-dAb) is 5.56-fold of the structure without AuNPs (cAb/CRP/dAb). Moreover, concentration of AuAg-SPR biosensor in CRP detection was lower for an order of magnitude than that of the conventional gold film cladding SPR (Au-SPR) biosensor, according to its direct reaction with the immobilized cAb. The dynamic field enhancement based AuAg-SPR biosensors have high sensitivity in detecting trace biomarker of CRP, and the improvement can also be applied to the detection of other biomarkers in low concentration sensitively.
Point of care testing (POCT) platforms are analytical devices used for rapid on-site sensing applications. POCT in sports science has attracted significant attention as the markers related to physiological changes and metabolism can be analysed on-site for monitoring an athlete’s health, performance, recovery and even for doping control. POCT platforms also possess the potential to facilitate trainers in optimizing the training regimes for preventing injuries, track their nutrition, and could potentially assist sports committees to enforce effective doping control measures during and outside competitions. This review is a consolidated report on emerging trends in POCT platforms in sports science. The methodologies reported thus far that have already been applied or possess a potential to be applied for detection of various sports biomarkers are elaborated. A comprehensive outlook is further provided, which would aid efforts on development of POCT platforms for a wide range of applications.
The design of a rapid, simple, and ultrasensitive detection platform of protein biomarkers has become an urgent need in early diagnosis and treatment. Surface-enhanced Raman scattering (SERS) technology, with the unique advantages of ultra-sensitivity and fingerprint recognition, has attracted much attention in biomarker detection. An innovative aptamer SERS biosensor for highly sensitive protein biomarker detection was presented. This biosensor contains a SERS tag (reporter-labeled Au nano-bridged nanogaps particles, Au NNPs) and novel magnetic capture substrate (Ag-coated Fe3O4-Au NPs, Ag MNPs). C-reactive protein (CRP), a representative biomarker for diagnosing, was used to assess the SERS performance of this biosensor. Aptamers against CRP were modified on both SERS tag and magnetic capture substrate for specific recognition by Au NNPs-CRP-Ag MNPs sandwich assay. This strategy achieved sensitive detection of CRP with a limit of detection (LOD) of 10 fM (1.14 pg/mL), and is much lower than reported analytical methods. Besides, this method exhibits excellent selectivity and specificity for CRP under the interference of other proteins and displays high accuracy in the detection of actual human serum samples. This proposed detection strategy can be extended to the sensitive detection of other biomarker proteins and hold great promise in the clinical diagnosis of diseases.
We report a self-sufficient microfluidic paper-based lateral flow immunoassay device (μLFD) for highly sensitive detection of the thyroidstimulatinghormone (TSH). Fabrication of the paper microchannels involves engraving the nitrocellulose membrane with a CO2 laser tocreate narrow flow paths, which constrain the fluid flow over the test zone. The proposed microchannel modified devices were studied fordetection of the TSH using gold nanoparticles as labels. The effect of such microchannel modified LFDs has led to an improvement insensitivity by nine times and the limit of detection by 6.6 times due to the slow flow rate of the sample compared with the traditional LFD.In addition, the binding of gold nanoparticles over the test line is more uniform in the case of the μLFD, thus minimizing leading-edge effects, resulting in more accurate quantitative analysis. The proposed strategy offers great potential for multiplex detection of biomarkers with increased sensitivity without introducing any hydrophobic materials to the LFD.
Viral and bacterial infections commonly occur by their transmission through air, contaminated food, water, body fluids or physical contact from person to person. They rapidly spread among the population causing millions of deaths worldwide. One of the major challenges in the diagnosis of infection is differential diagnosis of viral from bacterial infections. Constant viral mutations, reassortment and recombination give rise to the emergence of new and diverse viral populations which makes the diagnosis difficult. Antibiotics prescribed for patients suffering from viral infections are ineffective and a contributing factor to bacterial antibiotic resistance. Evaluating the existing biosensing platforms for early diagnosis of the bacterial etiology of infections enables researchers and clinicians to differentially diagnose viral infections. Over the last decade, many biosensors have been developed to detect a wide range of bacterial and viral markers and reduce the costs for healthcare. There has been considerable interest in finding diagnostic and prognostic biomarkers that can be detected in blood and predict bacterial and viral infections. This review provides an overview on the existing biosensor technology platforms for host biomarker detection that can be applied for differential diagnosis of viral and bacterial infections, as well as recommended considerations and future prospects of viral/bacterial infection detection technology.
The present PCR instrument is based on the Peltier semiconductor to achieve temperature cycling, but continuous photographing is not allowed and the self-contained timing software was seriously lagging. Therefore, from the perspective of photoelectric control, the conventional PCR machine was combined with a smartphone and PC, and an optical and electrical feedback automatic fluorescence detection system was designed to achieve quantitative real-time PCR. Through the script, camera timing was controlled by comparing the changes on the screen in the adjacent time, and automatic photo feedback is realized. This experiment has proven that this method can greatly improve the accuracy of the time to photograph and clearness of the photos. The smartphone connected to a computer installed on the PCR can be used after debugging. Compared with quantitative real-time PCR, conventional PCR is more cost-effective on the basis of detection requirements.
C-reactive protein (CRP) has become a recognized indicator of inflammation. CRP concentration in serum is an important indicator for monitoring early heart damage, and it is also a newly discovered coronary heart disease-associated inflammatory factor. A conductive nano-hybrid material composed of Au NPs and ionic liquid functionalized molybdenum disulfide (Au NPs/IL-MoS2) was prepared and utilized to immobilize primary CRP antibodies. Subsequently, 1,5-diaminonaphthalene (DN) was adsorbed onto graphene oxide (GO) through π–π stacking, which was used to load iridium nanoparticles (Ir NPs) as a tag to label secondary CRP antibodies. The large surface area of Au NPs/IL-MoS2 and the excellent electrocatalytic properties of Ir NPs/GO-DN toward the reduction of H2O2 resulted in a highly sensitive assay for CRP antigens. This immunosensor exhibited wide linear ranges from 0.01 to 100 ng mL⁻¹ and a lower detection of limit of 3.3 pg mL⁻¹ (S/N = 3). This CRP immunosensor can be applied in real serum sample analysis with satisfactory results, indicating that the immunosensor has potential applications in biomedical detection.
Smartphone (SP)-based devices and associated tools have emerged as ideal next-generation point-of-care devices (POCD) for in vitro diagnostics (IVD) of important physiological parameters including blood glucose level. Such devices with advanced features are anticipated to play an enhanced role in the future of cost-effective mobile healthcare (mH) and personalized medicine. The detection principle of the diversified SP-IVD devices encompasses optical, surface plasmon resonance, lateral flow, or electrochemical methods. Another appealing approach is the transformation of SP into a compact and inexpensive microscope or cytometer to detect biomolecules, metabolites, biomarkers, and pathogens. The exponential development of SP-IVD technologies will foster their widespread use in personalized mH in remote settings and, particularly, in developing countries with limited healthcare resources. The extent of private health data created by SP-IVD will herald the enlargement of Cloud-based technologies to securely transmit, store, and retrieve such confidential data across medical fraternity and policymakers.
Point-of-care (POC) technologies have advanced considerably during the last decade to pave the way to the emergence of next-generation healthcare monitoring and management. The most prominent developments encompass the smartphone (SP)-based technologies, paper-based assays (PBA), lab-on-a-chip (LOC) platforms, microfluidic operations, new biosensors, rapid assay formats, automated and fully integrated assay technologies, prolonged reagent storage concepts, and novel bioanalytical technologies. The advances in complementary technologies would provide considerable support to the development of critically improved POC technologies. Although paper- and LOC-based assays are cost-effective and simple, emerging SP-based technologies become the ideal POC solution for healthcare due to their enormous outreach and enriched features. Such POC technologies could increase the outreach of healthcare for remote and decentralized settings worldwide. The recent trend is strongly inclined toward mobile healthcare (mH), which would lead to critically improved healthcare monitoring and management.
Lab-on-a-chip (LOC)-based immunoassays (IAs) are one of the most prospective IA formats for the point-of-care (POC) detection of analytes at the point-of-need as they are simple, cost-effective, and rapid. Although the conventional POC IA formats are lateral flow assay (LFA), dipstick, and electrochemical strips, the most recent LOC-based POC IA platforms incorporate microfluidic (MF) chips, paper, cellphone (CP), electrochemistry, lateral flow, and new biosensor concepts. There is an extensive need for such LOC-based POC IAs for the low-cost diagnosis of diseases in the developing countries and remote settings. They don’t require skilled analysts, expensive instruments, and costly infrastructure. The current trend is strongly inclined toward the use of smartphones (SPs) as the POC readers or smart readers. The next-generation LOC-based POC IAs would be fully-automated, low-cost, and simple to operate. They will employ novel IA concepts, strategies for prolonged reagent storage, innovative biosensors, and high-throughput multiplex detection. This chapter discussed the various LOC-based POC IAs along with the future trends and challenges toward the development of clinically-viable immunodiagnostics.
We have developed a digital and multiplexed platform for the rapid detection and telemonitoring of infections caused by Ebola and Marburg filoviruses. The system includes a flow cell assay cartridge that captures specific antibodies with microarrayed recombinant antigens from all six species of filovirus, and a smartphone fluorescent reader for high-performance interpretation of test results. Multiplexed viral proteins, which are expandable to include greater numbers of probes, were incorporated to obtain highest confidence results by cross-correlation, and custom smartphone application was developed for data analysis, interpretation and communication. The smartphone reader utilizes an opto-electro-mechanical hardware attachment that snaps at the back of a Motorola smartphone which provides a user interface to manage the operation, acquire test results and communicate with cloud service. The application controls the hardware attachment to turn on LEDs and digitally record the optically enhanced images. Assay processing time is approximately 20 min for microliter amounts of blood, and test results are digitally processed and displayed within 15 seconds. Furthermore, a secure cloud service was developed for the telemonitoring of test results generated by the smartphone readers in the field. Assay system results were tested with sera from non-human primates that received a live attenuated EBOV vaccine. This integrated system will provide a rapid, reliable, and digital solution to prevent the rapid overwhelming of medical systems and resources during EVD or MVD outbreaks. Further, this disease-monitoring system will be useful in resource limited countries where there is a need for dispersed laboratory analysis of recent or active infections.
Plastic micro-chips with micro-pit array (μPACs) were used for the mobile phone mediated detection of HIV capsid p24 antigen. The μPACs with a size comparable to common test strips were fabricated on transparent cyclic olefin copolymer (COC) sheets to ensure the optical detection and solvent compatibility. An antibody (for p24 antigen) was covalently immobilized onto the inner surface of micro-pits for sandwich immunoassay. The enzyme-catalyzed reaction was imaged by a mobile phone and the captured pictures were sent to a computer (server) for quantitative analysis. Under the optimized condition, detection limits of 190 pg/ml and 650 pg/ml for p24 antigen were attained in buffer and spiked human serum, respectively. Low-cost of μPACs and easy operation combined with wide coverage of mobile phones network all over the world make the proposed method a competent candidate as a diagnostic tool in resource-limited settings.
A novel QD-based immunoassay on a paper-based lateral flow system has been developed to quantitatively detect C-reactive protein (CRP). Different standard CRP antigens from 1 to 200 μg mL⁻¹ were diluted 200-fold and only 60 μL diluted sample were needed to load onto the sample pad. The QD fluorescence signals on the test line and the control line were able to be observed within 3 min after the initiation of assay, and the limit of detection was as sensitive as 0.30 ng mL⁻¹ by measuring the fluorescence intensity immediately afterwards with fluorescence immunoassay analyzer. The linearity on the detection of QD fluorescence signals has been established well in the range of 0.5 ng mL⁻¹ and 1 μg mL⁻¹ for CRP. The precision of the assay has been confirmed for low coefficient of variation (CV), satisfying less than 15% (intra-assay and inter-assay), and the accuracy of assay meets the requirements with the mean recovery of the control was 102.63%. These results indicated that such newly developed platform was reliable with high sensitivity, rapidness, and could cover a broad range of target concentrations. Furthermore, a total of 135 human serum clinical samples with inflammation or infection with the concentration of CRP from 0.2 to 200 μg mL⁻¹ has been used to check the performance of this QD-based LFIA, it correlated very well with Roche Tina-quant CRP (Latex) (r = 0.966, n = 135).
Onsite rapid detection of herbicide and herbicide residuals in environmental and biological specimens is important for agriculture, environment, food safety, and health care. Traditional method for herbicide detection requires expensive laboratory equipment and a long turn-round time. In this work, we developed a single-stripe microliter plate smartphone colorimetric device for rapid and low-cost in-field test. This portable smartphone platform is capable of screening 8 samples in a microplate single-stripe. The device combined the advantages of small size (50×100×160 mm3) and low cost ($10). The platform was calibrated by using two different dye solutions, i.e. methyl blue (MB) and Rhodamine B, for green and red channels. The results showed good correlation with results attained from a traditional laboratory reader. We demonstrated the application of this platform for an herbicide, 2,4-Dichlorophenoxyacetic acid detection in the range of 1 ppb to 80 ppb. Spiked samples of tap water, rat serum, plasma and human serum were tested by our device. Recoveries obtained varied from 95.6% to 105.2% for all spiked samples using the microplate reader and from 93.7% to 106.9% using the smartphone device. This work validated that the smartphone optical sensing platform is comparable to the commercial microplate reader, it is eligible for onsite rapid and low-cost detection of herbicide for environmental evaluation and biological monitoring.
Smartphones and related accessories are rapidly expanding their applications in various fields. Herein we developed a smartphone coupled handheld array reader with the integration of complementary metal oxide (CMOS) image sensor for detecting various toxic gases by colorimetric monitoring approach. In this study, toxic gases such as hydrogen fluoride (HF), chlorine (Cl2), ammonia (NH3), and formaldehyde (CH2O) were detected using titanium nanoparticles (TiO2 NPs) blended poly (vinyl alcohol) (PVA) hydrogel test strips, which were patterned with chemically responsive dyes. The dye colors changed based on acid-base reactions, and the colorimetric reader monitored the array strips and mapped them in the form of chrominance data. The observed signals transferred to a smartphone that displays the detected toxic gases and their exposure levels with the aid of the smartphone app “Toxic Gas Detection”. The colorimetric array reader was precisely constructed with an auto-calibration system to minimize potential errors. Various concentration of toxic gases (0.5 to 10 ppm) were analyzed and achieved the detection limit of 1ppm for each gas. Also, various analytical performance including sensitivity, stability, selectivity, and reproducibility analysis proved the reliability and accuracy of the detection system. Additionally, the smartphone app can be installed on any type of tablet, laptop, or other portable device. This study proved that smartphone coupled colorimetric array reader is a suitable system for detecting various toxic gases, chemicals and biochemical analysis with real-time monitoring approach.
Bacterial whole cell-based biosensors have been genetically engineered to achieve selective and reliable detection of a wide range of hazardous chemicals. Although whole-cell biosensors demonstrate many advantages for field-based detection of target analytes, there are still some challenges that need to be addressed. Most notably, their often modest shelf life and need for special handling and storage make them challenging to use in situations where access to reagents, instrumentation, and expertise are limited. These problems can be circumvented by developing biosensors in Bacillus spores, which can be engineered to address all of these concerns. In its sporulated state, a whole cell-based biosensor has a remarkably long life span and is exceptionally resistant to environmental insult. When these spores are germinated for use in analytical techniques, they show no loss in performance, even after long periods of storage under harsh conditions. In this chapter, we will discuss the development and use of whole cell-based sensors, their adaptation to spore-based biosensors, their current applications, and future directions in the field.
In this study, our objective was to develop a photothermal biosensor (PTB) for measurement of C-reactive protein (CRP) concentrations in human saliva. The resulting PTB that we developed is rapid, simple, and minimally invasive, and can be used to measure the concentration of CRP in human saliva (7-μL sample volume). The CRP (0.1–100 ng/mL) is captured by the sandwich immunoassay on the sensor, and gold nanoparticles (GNPs) conjugated with antibodies cause a photothermal effect when irradiated with a laser (90 s, wavelength = 532 nm). The temperature changes caused by this effect correlate with the concentrations of CRP. Therefore, the sensor shows a higher correlation with the concentrations of CRP than commercial detection kits. Its detection limit is 0.1 ng/mL CRP.
Routine antimicrobial susceptibility testing (AST) can prevent deaths due to bacteria and reduce the spread of multi-drug-resistance, but cannot be regularly performed in resource-limited-settings due to technological challenges, high-costs, and lack of trained professionals. We demonstrate an automated and cost-effective cellphone-based 96-well microtiter-plate (MTP) reader, capable of performing AST without the need for trained diagnosticians. Our system includes a 3D-printed smartphone attachment that holds and illuminates the MTP using a light-emitting-diode array. An inexpensive optical fiber-array enables the capture of the transmitted light of each well through the smartphone camera. A custom-designed application sends the captured image to a server to automatically determine well-turbidity, with results returned to the smartphone in ~1 minute. We tested this mobile-reader using MTPs prepared with 17 antibiotics targeting Gram-negative bacteria on clinical isolates of Klebsiella pneumoniae, containing highly-resistant antimicrobial profiles. Using 78 patient isolate test-plates, we demonstrated that our mobile-reader meets the FDA-defined AST criteria, with a well-turbidity detection accuracy of 98.21%, minimum-inhibitory-concentration accuracy of 95.12%, and a drug-susceptibility interpretation accuracy of 99.23%, with no very major errors. This mobile-reader could eliminate the need for trained diagnosticians to perform AST, reduce the cost-barrier for routine testing, and assist in spatio-temporal tracking of bacterial resistance.
In recent years, graphene and related two-dimensional (2D) materials have emerged as exotic materials in nearly every fields of fundamental science and applied engineering. The latest progress has shown that these 2D materials could have a profound impact on bioelectronics devices. For the construction of these bioelectronics devices, these 2D materials were generally synthesized by the processes of exfoliation and chemical vapor deposition. In particular, the macrostructures of these 2D materials have also been realized by the two processes, which have shown great potentials in the self-supported and special-purpose biosensors. Due to the high specific surface area, subtle electron properties, abundant surface atoms of the 2D materials, the as-constructed bioelectronics devices have exhibited enhanced performance in the sensing of small biomolecules, heavy metals, pH, protein and DNA. The aim of this review article is to provide a comprehensive scientific progress in the synthesis of the 2D materials for the construction of five typical bioelectronics devices (electrochemical biosensors, FET-based biosensors, piezoelectric devices, electrochemiluminescence devices and supercapacitors) and to overview the present status and future perspective of the applications of these bioelectronics devices based on the 2D materials.
Plasmonic nanosensors may be used as tools for diagnostic testing in the field of medicine. However, quantification of plasmonic nanosensors often requires complex and bulky readout instruments. Here, we report the development of a portable smart phone-based plasmonic nanosensor readout platform (PNRP) for accurate quantification of plasmonic nanosensors. This device operates by transmitting excitation light from a LED through a nanosubstrate and measuring the intensity of the transmitted light using the ambient light sensor of a smart phone. The device is a cylinder with a diameter of 14 mm, a length of 38 mm, and a gross weight of 3.5 g. We demonstrated the utility of this smart phone-based PNRP by measuring two well-established plasmonic nanosensors with this system. In the first experiment, the device measured the morphology changes of triangular silver nanoprisms (AgNPRs) in an immunoassay for the detection of carcinoembryonic antigen (CEA). In the second experiment, the device measured the aggregation of gold nanoparticles (AuNPs) in an aptamer-based assay for the detection of adenosine triphosphate (ATP). The results from the smart phone-based PNRP were consistent with those from commercial spectrophotometers, demonstrating that the smart phone-based PNRP enables accurate quantification of plasmonic nanosensors.
Smartphone-based devices and applications (SBDAs) with cost effectiveness and remote sensing are the most promising and effective means of delivering mobile healthcare (mHealthcare). Several SBDAs have been commercialized for the personalized monitoring and/or management of basic physiological parameters, such as blood pressure, weight, body analysis, pulse rate, electrocardiograph, blood glucose, blood glucose saturation, sleeping and physical activity. With advances in Bluetooth technology, software, cloud computing and remote sensing, SBDAs provide real-time on-site analysis and telemedicine opportunities in remote areas. This scenario is of utmost importance for developing countries, where the number of smartphone users is about 70% of 6.8 billion cell phone subscribers worldwide with limited access to basic healthcare service. The technology platform facilitates patient-doctor communication and the patients to effectively manage and keep track of their medical conditions. Besides tremendous healthcare cost savings, SBDAs are very critical for the monitoring and effective management of emerging epidemics and food contamination outbreaks. The next decade will witness pioneering advances and increasing applications of SBDAs in this exponentially growing field of mHealthcare. This article provides a critical review of commercial SBDAs that are being widely used for personalized healthcare monitoring and management.
Background In August 2012, new national guidance (National Institute of Health and Care Excellence (NICE) CG149) for management of early onset sepsis (EOS) was introduced in the UK. The guidance outlined a consistent approach for septic screens in newborn infants based on risk factors, and suggested biochemical and clinical parameters to guide management. In particular, it advised a second C-reactive protein level (CRP) 18–24 h into treatment to help determine length of antibiotic course, need for lumbar puncture (LP), and suggested review of blood culture at 36 h.
Objective We evaluated impact of this guidance in our neonatal unit.
Methods We compared two time periods, before and following the guidance. We evaluated length of stay, second CRP 18–24 h into treatment, percentage of babies having LP and duration of antibiotics.
Results Before NICE guidance, 38.1% of screened babies stayed <72 h. This reduced to 18.4% following guidance. Before guidance, 20.9% babies stayed >5 days, which increased to 27.7% following NICE recommendations. Repeat CRP measurements increased from 45% to 97%. In 58% of these babies, repeat CRPs influenced management and hospital stay. An increase in LPs performed from 14% to 23% was noted. There were no positive blood cultures or LP results.
Conclusions We envisaged shorter hospital stays with new NICE standards, particularly, with the aim of 36 h blood culture reporting. However, repeat CRP led to further investigations, increased LPs and longer durations of treatment and stay. This, in turn, impacted on workload and cost, and influenced parental experience in the first few days of life.
Introduction: Diabetes mellitus (DM) is one of the metabolic
syndromes prevalent worldwide, with more concentration in the
Asian region. Many studies have been conducted in order to
understand the complex pathogenesis of this disease. Yet, there
exists a lacuna in our knowledge about DM. This study aims at
establishing the reason for glycemic variation in menstruating
Type-2 diabetic women by estimation of C-reactive protein, an
inflammatory marker that exhibits significant association with
changes in blood glucose levels.
Methodology: A prospective study was undertaken in Type-2
diabetic women of reproductive age group to assess the
variability of glycemic control during different phases of menstrual
cycle using high sensitivity C reactive protein (hs-CRP) as the
biomarker. Fifty women were enrolled after satisfying a set of
inclusion and exclusion criteria. The fasting blood glucose, hsCRP concentration and endogenous female hormones were
assayed in follicular and luteal phases of the cycle. The observed
parameters were analyzed statistically for significant correlation.
Observation and Result: The result showed that hs-CRP level
significantly correlates with increasing levels of fasting blood
glucose level in both the phases of menstrual cycle in Type-2
diabetic women. The significance is statistically stronger during
luteal phase of the cycle (r = 0.807; p
An improved enzyme-linked immunosorbent (ELISA) assay using one-step antibody immobilization has been developed for the detection of human fetuin A (HFA), a specific biomarker for atherosclerosis and hepatocellular carcinoma. The anti-HFA formed a stable complex with 3-aminopropyltriethoxysilane (APTES) by ionic and hydrophobic interactions. The complex adsorbed on microtiter plates exhibited a detection range of 4.9 pg mL(-1) to 20 ng mL(-1) HFA, with a limit of detection of 7 pg mL(-1). Furthermore, an analytical sensitivity of 10 pg mL(-1) was achieved, representing a 51-fold increase in sensitivity over the commercial sandwich ELISA kit. The results obtained for HFA spiked in diluted human whole blood and plasma showed the same precision as the commercial kit. When stored at 4°C in 0.1 M phosphate-buffered saline (PBS, pH 7.4), the anti-HFA bound microtiter plates displayed no significant decrease in their functional activity after two months. The new ELISA procedure was extended for the detection of C-reactive protein, human albumin and human lipocalin-2 with excellent analytical performance.
1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) alone, and in combination with N-hydroxysuccinimide (NHS) or sulfoNHS were employed for crosslinking anti-human fetuin A (HFA) antibodies on 3-aminopropyltriethoxysilane (APTES)-functionalized surface plasmon resonance (SPR) gold chip and 96-well microtiter plate. The SPR immunoassay and sandwich enzyme linked immunosorbent immunoassay (ELISA) for HFA clearly demonstrated that EDC crosslinks anti-HFA antibodies to APTES-functionalized bioanalytical platforms more efficiently than EDC/NHS and EDC/sulfoNHS at a normal pH of 7.4. Similar results were obtained by sandwich ELISAs for human Lipocalin-2 and human albumin, and direct ELISA for horseradish peroxidase. The more efficient crosslinking of antibodies by EDC to the APTES-functionalized platforms increased the cost-effectiveness and analytical performance of our immunoassays. This study will be of wide interest to researchers developing immunoassays on APTES-functionalized platforms that are being widely used in biomedical diagnostics, biosensors, lab-on-a-chip and point-of-care-devices. It stresses a critical need of an intensive investigation into the mechanisms of EDC-based amine-carboxyl coupling under various experimental conditions.
Several biochemical markers have been proposed over the past years to manage critically ill newborns with acute inflammation and sepsis. The state of the art in diagnosing and monitoring neonatal sepsis, severe sepsis and septic shock consists of the measurement of plasma C-reactive protein (CRP) and procalcitonin (PCT) at the onset and in the course of the disease. CRP and PCT in combination are clinically significant in diagnosing and monitoring septic newborns; however, CRP and PCT have a very limited value for risk stratification and in predicting outcome. The availability of commercial methods for the automated measurement of the soluble CD14 subtype presepsin (sCD14-ST) and lipopolysaccharide binding protein (LBP) represent a challenge for the evaluation in clinical practice of reliable markers of neonatal sepsis, specifically for the very early diagnosis, the classification into class of severity, and the prediction of complications and death.
The non-specific loss of protein analytes can have a major effect on assay results particularly where the concentrations of such analytes are extremely low and the matrix is complex. This report assesses how the protein incubated in sample tubes may be lost due to adsorption. Use of proteins, such as bovine serum albumin (BSA), may be used to pre-treat tubes to reduce such losses. However, such losses may also be associated with structural perturbations leading to changes in immunogenicity (as a result of alterations in specific epitope-related conformations). This can lead to erroneous results or lack of comparability with a range of methodologies such as the bicinchoninic protein assay and immunoassays or when surface plasmon resonance (SPR)-based approaches are used. A model system to evaluate these phenomena is proposed.
The evaluation of tests for neonatal sepsis is important because the infection may present a very serious threat to the baby. There is an urgent need to know whether the baby has sepsis to institute treatment as quickly as possible. Confirmation of the diagnosis may take time, and diagnostic tests are used to obtain a rapid indication of the infection status. These tests are not perfect. Some real cases of infection will produce negative test results, whereas some babies without infection will test positive. The potential usefulness of the test will depend, above all, on the clinical condition of the baby. If the baby is really very sick, the test will not give very much additional information. Similarly, if the baby is evidently well, a clinical examination will be sufficient and a positive test result would not dramatically increase the probability that the baby is infected. It is in situations in which the clinical picture leaves the physician in doubt about the infection status that a diagnostic test is likely to be most useful. Thus, the result of a diagnostic test must be evaluated in the light of the clinical condition of the baby.
Extensive literature exists on single laboratory tests or combinations of tests, as well as tests used together with risk factors and/or clinical signs, to diagnose neonatal sepsis. In many instances, the results of the evaluations have been conflicting. There are several possible explanations for the divergent results, and the purpose of this review is to update readers on the topic and raise issues that should be addressed in the future.
Throughout pregnancy and until the membranes rupture, the fetus is relatively protected from the microbial flora of the mother by the chorioamniotic membranes, the placenta, and poorly understood antibacterial factors in amniotic fluid (1). However, there …
Increasing amounts of data suggest that inflammatory responses have an important role in the pathophysiology of depression. Depressed patients have been found to have higher levels of proinflammatory cytokines, acute phase proteins, chemokines and cellular adhesion molecules. In addition, therapeutic administration of the cytokine interferon-alpha leads to depression in up to 50% of patients. Moreover, proinflammatory cytokines have been found to interact with many of the pathophysiological domains that characterize depression, including neurotransmitter metabolism, neuroendocrine function, synaptic plasticity and behavior. Stress, which can precipitate depression, can also promote inflammatory responses through effects on sympathetic and parasympathetic nervous system pathways. Finally, depression might be a behavioral byproduct of early adaptive advantages conferred by genes that promote inflammation. These findings suggest that targeting proinflammatory cytokines and their signaling pathways might represent a novel strategy to treat depression.
Biomolecules and cells are critical components of biosensors and biomaterials, but in order to function in an artificial environment, they must be immobilized in a manner that does not affect their interaction with target analytes. Biosensors demonstrate that we can harness the incredible functions of living molecules and cells for our own purposes and are therefore at the forefront of technology. Moreover the applications of immobilized biomolecules and cells are expected to expand far beyond biosensor applications and indeed are already used for pharmaceutical production and testing. Biomaterials will become increasing common as they are being developed into toxic filters, artificial organs, and even silicon chips. This book provides a selection of methods for the immobilization of biomolecules and cells on a variety of surface with different geometries and chemistries so that they retain their function and guidelines on which method to use. Also included are the analytical techniques to measure the functionality of immobilized biomolecules. All the protocols have been tried and validated by the authors. Immobilized Biomolecules in Analysis: A Practical Approach is an invaluable guide to all researchers in the fields of biosensors and biomaterials. Research in biosensors is carried out in a wide variety of fields including biochemistry, chemistry, engineering, laboratory medicine, environmental and defence research. The protocols are written so that an extensive prior knowledge of biochemistry is not required to use them.
High-sensitivity C-reactive protein (hsCRP) is a marker of inflammation that predicts incident myocardial infarction, stroke, peripheral arterial disease, and sudden cardiac death among healthy individuals with no history of cardiovascular disease, and recurrent events and death in patients with acute or stable coronary syndromes. hsCRP confers additional prognostic value at all levels of cholesterol, Framingham coronary risk score, severity of the metabolic syndrome, and blood pressure, and in those with and without subclinical atherosclerosis. hsCRP levels of less than 1, 1 to 3, and greater than 3 mg/L are associated with lower, moderate, and higher cardiovascular risks, respectively. This article summarizes epidemiologic data on the relation between CRP and atherothrombotic disease and provides clinical guidelines for hsCRP screening in cardiovascular risk assessment.
Bacterial infections can be a devastating complication in the newborn and continue to be a significant cause of mortality and long-term morbidity of hospitalized newborns and premature infants. The diagnosis of neonatal sepsis is difficult to establish and remains a challenge for neonatal health care providers. Early signs and symptoms of neonatal sepsis are often nonspecific and easily confused with conditions that are expected in this population. Neonatal care providers have evaluated numerous tests searching for one that would be helpful in the diagnosis of neonatal sepsis, one that quickly confirms the diagnosis, and one that conclusively rules it out. This article examines the tests in current use and some of the more recent diagnostic markers used alone or in combination to improve sensitivity and specificity for early detection of sepsis.
Biosensing and diagnostic platforms with high sensitivity, specificity, and fast response time are based on immobilized biomolecules such as antibodies (Abs), aptamers, enzymes, nucleic acids, receptors, and whole cells for the detection of target analytes. Such sensing biomolecules should be bound to the surface of a signal transducer with a required specific chemical, electrical, or optical property. The biological recognition event generates a quantifiable signal, which is equated to the amount or concentration of the analyte. APTES can be deposited on solid materials, electrode materials, nanomaterials, and nanocomposites under variable conditions of concentration, solvent, temperature, and time. In addition, curing conditions such as air/heat drying might be necessary depending upon the intended application. Pertinent information on the thickness, morphology, and conformation of the APTES layer reported in the literature is often different and conflicting.
A smartphone-based colorimetric reader (SBCR) was developed using a Samsung Galaxy SIII mini, a gadget (iPAD mini, iPAD4 or iPhone 5s), integrated with a custom-made dark hood and base holder assembly. The smartphone equipped with a back camera (5 megapixels resolution) was used for colorimetric imaging via the hood and base-holder assembly. A 96- or 24-well microtiter plate (MTP) was positioned on the gadget's screensaver that provides white light-based bottom illumination only in the specific regions corresponding to the bottom of MTP's wells. The pixel intensity of the captured images was determined by an image processing algorithm. The developed SBCR was evaluated and compared with a commercial MTP reader (MTPR) for three model assays: our recently developed human C-reactive protein sandwich enzyme-linked immunosorbent assay (ELISA), horseradish peroxidase direct ELISA, and bicinchoninic acid protein estimation assay. SBCR had the same precision, dynamic range, detection limit and sensitivity as MTPR for all three assays. With advanced microfabrication and data processing, SBCR will become more compact, lighter, inexpensive and enriched with more features. Therefore, SBCR with a remarkable computing power could be an ideal point-of-care (POC) colorimetric detection device for the next-generation of cost-effective POC diagnostics, immunoassays and diversified bioanalytical applications.
We report the preparation and application of biofunctional nanoparticles to detect C-reactive protein (CRP) in magnetic microplates. A CRP model biomarker was used to test the proposed detection method. Biofunctional magnetic nanoparticles, CRP, and biofunctional fluorescent nanoparticles were used in a sandwich nanoparticle immunoassay. The CRP concentrations in the samples were deduced from the reference plot, using the fluorescence intensity of the sandwich nanoparticle immunoassay. When biofunctional nanoparticles were used to detect CRP, the detection limit was 1.0 ng ml(-1) and the linear range was between 1.18 ng ml(-1) and 11.8 μg ml(-1). The results revealed that the method involving biofunctional nanoparticles exhibited a lower detection limit and a wider linear range than those of the enzyme-linked immunosorbent assay (ELISA) and most other methods. For CRP measurements of serum samples, the differences between this method and ELISA in CRP measurements of serum samples were less than 13%. The proposed method can reduce the analysis time to one-third that of ELISA. This method demonstrates the potential to replace ELISA for rapidly detecting biomarkers with a low detection limit and a wide dynamic range.
The lateral flow assay (LFA) strip sensor possesses many advantages as a diagnostic device, including the capabilities of rapid, one-step assay performance, and high throughput production. A major limitation of the sensor, however, is its difficulty in measuring a broad concentration range of target proteins, including C-reactive protein (CRP), due to the "hook effect." In this study, we report the use of a three-line LFA strip sensor, adding an antigen line to the conventional two-line LFA sensor, for detecting CRP within a broad concentration range in human sera. We introduced an antigen line between test and control lines in the LFA sensor. The antigen line was formed by dispensing a CRP antibody solution followed by a CRP solution in nitrocellulose membrane. All other conditions were identical to those applied to the conventional LFA strip sensor. The CRP level in test samples was generated by data processing from the intensities of three lines. The strip sensor measured a linear detection range of CRP concentration from 1ng/mL to 500μg/mL within 10min, with a calculated detection range of 0.69ng/mL-1.02mg/mL. Using the developed three-line LFA sensor, 50 clinical samples were measured at a detection range of 0.4-84.7μg/mL. This novel and easy-to-use CRP sensor can be a useful tool for rapid, sensitive, and cost-effective detection of a broad physiological concentration range of CRP capabilities that are vital for various diagnostic applications.
The article reveals a rapid sandwich enzyme-linked immunosorbent assay (ELISA) for the highly-sensitive detection of human C-reactive protein (CRP) in less than 30 min. It employs a one-step kinetics-based highly simplified and cost-effective sandwich ELISA procedure with minimum process steps. The procedure involves the formation of a sandwich immune complex on capture anti-human CRP antibody-bound Dynabeads(®) in 15 min followed by two magnet-assisted washings and one enzymatic reaction. The developed sandwich ELISA detects CRP in the dynamic range of 0.3-81 ng mL(-1) with a limit of detection and analytical sensitivity of 0.4 ng mL(-1) and 0.7 ng mL(-1), respectively. It detects CRP spiked in diluted human whole blood and serum with high analytical precision as confirmed by conventional sandwich ELISA. Moreover, the results of the developed ELISA for the determination of CRP in the ethylenediaminetetraacetic acid (EDTA) plasma samples of patients are in good agreement with those obtained by the conventional ELISA. The developed immunoassay has immense potential for the development of rapid and cost-effective in vitro diagnostic kits.
IL-1 is a master cytokine of local and systemic inflammation. With the availability of specific IL-1 targeting therapies, a broadening list of diseases has revealed the pathologic role of IL-1-mediated inflammation. Although IL-1, either IL-1α or IL-1β, was administered to patients in order to improve bone marrow function or increase host immune responses to cancer, these patients experienced unacceptable toxicity with fever, anorexia, myalgias, arthralgias, fatigue, gastrointestinal upset and sleep disturbances; frank hypotension occurred. Thus it was not unexpected that specific pharmacological blockade of IL-1 activity in inflammatory diseases would be beneficial. Monotherapy blocking IL-1 activity in a broad spectrum of inflammatory syndromes results in a rapid and sustained reduction in disease severity. In common conditions such as heart failure and gout arthritis, IL-1 blockade can be effective therapy. Three IL-1blockers have been approved: the IL-1 receptor antagonist, anakinra, blocks the IL-1 receptor and therefore reduces the activity of IL-1α and IL-1β. A soluble decoy receptor, rilonacept, and a neutralizing monoclonal anti-interleukin-1β antibody, canakinumab, are also approved. A monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α are in clinical trials. By specifically blocking IL-1, we have learned a great deal about the role of this cytokine in inflammation but equally important, reducing IL-1 activity has lifted the burden of disease for many patients.
Graphene, graphene oxide, sulfonated graphene, and sulfonated graphene oxide (SGO) have been prepared, characterized and tested for the dehydration of xylose to furfural in water. In particular, SGO was proven to be a rapid and water-tolerant solid acid catalyst even at very low catalyst loadings down to 0.5wt.% vs xylose, maintaining its initial activity after 12 tested repetitions at 200°C, with an average yield of 61% in comparison to 44% for the uncatalyzed system. Raman spectroscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, 13C solid state nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and surface area analysis suggested that the aryl sulfonic acid groups were the key active sites for high temperature production of furfural in water. They were more thermally stable under the reaction conditions and acidic than other functional groups attached to the graphene surface.
C-reactive protein (CRP) was identified in 1930 and was subsequently considered to be an “acute phase protein,” an early indicator of infectious or inflammatory conditions. Since its discovery, CRP has been studied as a screening device for inflammation, a marker for disease activity, and as a diagnostic adjunct. Improved methods of quantifying CRP have led to increased application to clinical medicine. In the emergency department (ED), CRP must be interpreted in the clinical context; no single value can be used to rule in or rule out a specific diagnosis. We conclude that CRP has limited utility in the ED. It may be a useful adjunct to serial examinations in equivocal presentations of appendicitis in those centers without ready access to computed tomography (CT) scan. It may be elevated with complications or treatment failures in patients with pneumonia, pancreatitis, pelvic inflammatory disease (PID), and urinary tract infections. In patients with meningitis, neonatal sepsis, and occult bacteremia, CRP is usually elevated. However, CRP has no role in diagnosing these clinical entities, and a normal CRP level should never delay antibiotic coverage.
C-reactive protein (CRP) is a well-known inflammation marker in human beings. This study reports a new microfluidic system for fast, automatic detection of CRP. It contains pneumatic micropumps, a vortex-type micromixer, a pneumatic micro-injector and several microvalves to automatically perform the entire protocol for CRP detection. This includes sample/reagent transportation, incubation between the target CRP and a CRP-specific aptamer, washing processes, and the chemiluminescence development process. In addition, the chemiluminescence signal is measured by using a custom-made optical system which consists of a photomultiplier tube, a portable air compressor and eight electronic magnet valves to quantify the concentration of CRP. When compared to previous works, not only can this new microfluidic system automatically perform the entire process via a new integrated micro-injector and new micropumps, but a new CRP-specific DNA aptamer with a higher affinity and specificity is also used for CRP measurement. Experimental data show that the developed system can automatically complete the entire protocol within 30min with a detection limit of 0.0125mg/L, which is superior to previous published results. Moreover, this study also measures CRP concentration from clinical samples to verify the performance of the developed microfluidic system. The results indicate that the measured CRP concentrations from human serums are consistent with those using a benchtop system. The developed system can also detect CRP concentrations from human whole blood without any external sample pretreatment process. This microfluidic system may be promising for point-of-care applications for CRP detection in the future.
The measurement of serum C-reactive protein (CRP) levels has been given particular interest as a marker of inflammation associated with cardiovascular diseases. CRP belongs to the pentraxin family of proteins and the routine clinical analysis of CRP in blood samples is used as an important factor in primary prevention programmes together with causative and predisposing factors. This review focuses on the most representative methodologies and strategies for CRP detection and quantification that have been recently proposed, as well as reviewing those that are currently being developed for the specific, sensitive, inexpensive and high-throughput blood analysis of this protein.
Interleukin-1 (IL-1) is a highly active pro-inflammatory cytokine that lowers pain thresholds and damages tissues. Monotherapy blocking IL-1 activity in autoinflammatory syndromes results in a rapid and sustained reduction in disease severity, including reversal of inflammation-mediated loss of sight, hearing and organ function. This approach can therefore be effective in treating common conditions such as post-infarction heart failure, and trials targeting a broad spectrum of new indications are underway. So far, three IL-1-targeted agents have been approved: the IL-1 receptor antagonist anakinra, the soluble decoy receptor rilonacept and the neutralizing monoclonal anti-IL-1β antibody canakinumab. In addition, a monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α antibody are in clinical trials.
High-sensitivity C-reactive protein (hsCRP) and coronary artery plaque characteristics have been separately evaluated as prognosticators of adverse cardiovascular events; however, their relationship remains unclear. We therefore evaluated the prognostic value of hsCRP in relation to plaque subtypes in predicting adverse cardiovascular outcome in asymptomatic patients without known coronary artery disease.
A total of 4690 asymptomatic patients who underwent coronary computed tomography angiography for screening purposes were included. HsCRP was categorized as <1 mg/L, 1-3 mg/L and >3 mg/L. Cardiovascular events were defined as cardiovascular death, acute coronary syndrome, and stroke.
During follow-up (median 49 months, interquartile range 34-59 months), adverse cardiovascular events were observed in 56 (1.2%) patients. Higher hsCRP was associated with poor outcome in overall patients (OR 2.716, 95% CI 1.512-4.880, p = 0.001 for hsCRP 1-3 mg/L, OR 2.705, 95% CI 1.239-5.908, p = 0.013 for hsCRP > 3 mg/L, hsCRP <1 mg/L as reference). When patients were evaluated according to plaque subtype, hsCRP > 3 mg/L was a significant predictor of poor outcome only in patients with noncalcified plaques (NCP; p = 0.038). After adjusting for Framingham risk and coronary artery calcium score, hsCRP > 3 mg/L was a significant predictor of adverse outcomes in the presence of NCP (p = 0.048) but not in the presence of CP or MCP (p = 0.742).
Elevated hsCRP is a predictor of adverse cardiovascular events in asymptomatic patients with NCP. After adjusting for Framingham risk and coronary artery calcium scores, hsCRP > 3 mgL remained an independent predictor of risk in patients with NCP but not in patients with CP or MCP.
C-reactive protein (CRP) is an acute phase protein whose levels are increased in many disorders. There exists, in particular, a great deal of interest in the correlation between blood serum levels and the severity of risk for cardiovascular disease. A sensitive, label-free, non-amplified and reusable electrochemical impedimetric biosensor for the detection of CRP in blood serum was developed herein based on controlled and coverage optimised antibody immobilization on standard polycrystalline gold electrodes. Charge transfer resistance changes were highly target specific, linear with logCRPconcentration across a 0.5-50nM range and associated with a limit of detection of 176pM. Significantly, the detection limits are better than those of current CRP clinical methods and the assays are potentially cheap, relatively automated, reusable, multiplexed and highly portable. The generated interfaces were capable not only of comfortably quantifying CRP across a clinically relevant range of concentrations but also of doing this in whole blood serum with interfaces that were, subsequently, reusable. The importance of optimising receptor layer resistance in maximising assay sensitivity is also detailed.
Reflectometric interference spectroscopy (RIfS) is a label-free, time-resolved technique, and suitable for detecting antibody-antigen interaction. This work describes a continuous flow biosensor for C-reactive protein (CRP), involving an effective immobilization method of a monoclonal antibody against CRP (anti-CRP) to achieve highly sensitive RIfS-based detection of CRP. The silicon nitride-coated silicon chip (SiN chip) for the RIfS sensing was first treated with trimethylsilylchloride (TMS), followed by UV-light irradiation to in situ generation of homogeneous silanols on the surface. Following amination by 3-aminopropyltriethoxysilane, carboxymethyldextran (CMD) was grafted, and subsequently, protein A was immobilized to create the oriented anti-CRP surface. The immobilization process of protein A and anti-CRP was monitored with the RIfS system by consecutive injections of an amine coupling reagent, protein A and anti-CRP, respectively, to confirm the progress of each step in real time. The sensitivity was enhanced when all of the processes were adopted, suggesting that the oriented immobilization of anti-CRP via protein A that was coupled with the grafted CMD on the aminated surface of TMS-treated SiN chip. The feasibility of the present sensing system was demonstrated on the detection of CRP, where the silicon-based inexpensive chips and the simple optical setup were employed. It can be applied to other target molecules in various fields of life science as a substitute of surface plasmon resonance-based expensive sensors.
Aim:
The aim of this study was to determine the relationship between the development of diabetes mellitus and high-sensitivity C-reactive protein (HsCRP) adjusted for various potential confounders.
Methods:
This 5-year prospective cohort study was conducted at a Japanese steel factory and involved male workers who had received annual health screenings between 2005 and 2010. The 7392 male participants were aged 19-75 years. The study endpoint, the development of diabetes mellitus, was defined as HbA(1c) greater or equal to 6.5% or the use of antidiabetic medication. The association between variables was investigated using pooled logistic regression adjusted for various covariates such as age, baseline body mass index (BMI) and increase in BMI from baseline, blood biochemistry, job schedule and job-related stress.
Results:
The incidence rate of diabetes development per 1000 person-years was 13.9. Multivariate analysis showed a significant relationship between the development of diabetes and elevated levels of baseline HsCRP and increases in levels from baseline. The Odds ratios for a 2.9-fold (±1 geometric standard deviation) increase in baseline HsCRP and increase in HsCRP level from baseline were 1.18 [95% confidence interval (CI): 1.03-1.34; P=0.018] and 1.21 (95% CI: 1.03-1.41; P=0.018), respectively.
Conclusion:
The present study has indicated that HsCRP is an independent predictor for the development of diabetes in men, together with various confounders such as BMI, type of job schedule and job-related stress.
1.1. In order to determine the molecular weights of C-reactive protein and of Cx-reactive protein as they occur in serum, acute phase human and rabbit sera were studied by gel filtration and density gradient centrifugation techniques. The average value found for the mean molecular radius of serum C-reactive protein was 48.8 Å (range 48.6–49.0 Å). The sedimentation coefficient was 6.6 S (range 6.5–6.7 S). The approximate molecular weight of C-reactive protein as it exists in serum, calculated from these values, lies between 135 000 and 140 000, consistent with a molecule composed of 6 subunits of approximate molecular weight 23 000. The presence in serum of a pentameric form as well was suggested by an asymmetric elution pattern on gel filtration.2.2. The average sedimentation constant of serum Cx-reactive protein was 6.4 S (range 6.25–6.6 S) and the Stokes radius 43.2 Å (range 42.7–43.7 Å). Calculations based on these values indicated an approximate molecular weight lying between 114 000 and 123 000. Evidence for multiple polymeric forms was not obtained for Cx-reactive protein.3.3. Diffusion rates of C-reactive protein and of Cx-reactive protein in agarose were identical for all acute phase sera tested, permitting the use of radial diffusion techniques for quantitation of these acute phase proteins.
The high prevalence of cardiovascular diseases (CVD) demands a reliable and sensitive risk assessment technique. In order to develop a fast and label-free immunosensor for C-reactive protein (CRP), a risk factor for this condition, anti-CRP antibodies were physically adsorbed to the hydrogen (H)-terminated surface of nanocrystalline diamond (NCD). An Enzyme-Linked ImmunoSorbent Assay (ELISA) reference technique showed that this was a suitable substrate for antibody–antigen recognition reactions. Electrochemical Impedance Spectroscopy (EIS) was used to electronically detect CRP recognition. The specificity of the immunosensor was demonstrated by incubation with CRP and plasminogen as reference molecule. A different impedance behavior was observed in real-time after CRP addition as compared to plasminogen addition: the impedance increased only during CRP incubation. Fitting the data showed that this corresponded with a decrease in capacitance of the molecular layer due to its increased thickness by specific CRP recognition. Sensitivity experiments in real-time showed a clear discrimination between 1μM, 100nM, and 10nM of CRP after 10min at 100Hz. Since, 10nM of CRP was still clearly distinguishable from buffer solution, our CRP-directed immunosensor prototype reaches a sensitivity that is within the physiologically relevant concentration range of this biomarker in healthy controls and CVD patients. Moreover, this prototype displayed real-time discriminating power between spiked and unspiked serum, and thus also shows its applicability in this biological matrix.
We report on chemiluminescence resonance energy transfer (CRET) between graphene nanosheets and chemiluminescent donors. In contrast to fluorescence resonance energy transfer, CRET occurs via nonradiative dipole-dipole transfer of energy from a chemiluminescent donor to a suitable acceptor molecule without an external excitation source. We designed a graphene-based CRET platform for homogeneous immunoassay of C-reactive protein (CRP), a key marker for human inflammation and cardiovascular diseases, using a luminol/hydrogen peroxide chemiluminescence (CL) reaction catalyzed by horseradish peroxidase. According to our results, anti-CRP antibody conjugated to graphene nanosheets enabled the capture of CRP at the concentration above 1.6 ng mL(-1). In the CRET platform, graphene played a key role as an energy acceptor, which was more efficient than graphene oxide, while luminol served as a donor to graphene, triggering the CRET phenomenon between luminol and graphene. The graphene-based CRET platform was successfully applied to the detection of CRP in human serum samples in the range observed during acute inflammatory stress.
Objective:
Interest in cardiovascular diseases (CVD) in schizophrenia has grown recently due to documented incremental mortality. C-reactive protein (CRP) has been assessed as a marker in individuals with CVD and/or at high risk of developing it. However, its role in schizophrenia patients is unknown. The goal of this research was thus to explore the use of CRP as a marker of CVD risk in patients with schizophrenia.
Methods:
A cross-sectional analysis of the Badalona Serveis Assistencials (BSA) administrative claims database was conducted including all subjects aged>18 years with a diagnosis of schizophrenia spectrum disorder. CRP measurement, sociodemographics, medical history, 10-year CVD risk (Framingham function) and clinical chemistry data were extracted for analysis.
Results:
Seven hundred and five patients (53.0% men, 48.2 [15.8] years, 78.7% on atypicals) met criteria for analysis. Mean 10-year CVD risk was high; 11.9±5.7% and mean CRP levels were 2.6±2.5 mg/L with 30.4% showing above-normative levels (>3 mg/L). After adjusting for age, gender, smoking and presence of neoplasm or inflammatory diseases, CRP was linearly associated with 10-year CVD risk stratified by risk (low, moderate, high/very high): respectively, 2.3 (95% CI: 2.1-2.5), 3.1 (2.6-3.5) and 3.7 (3.2-4.1) mg/L; F=13.5, P<0.001. Patients with known CVD also showed higher CRP levels: 3.7 (2.9-4.5) vs. 2.5 (2.4-2.7) mg/L, P=0.008; and higher probability of above-normal values; odds ratio=4.71 (2.01-11.04), P<0.001.
Conclusions:
High CRP levels above normative were associated with both known CVD and high/very high 10-year risk of a CVD event in patients with schizophrenia, suggesting CRP could be a marker of CVD in this psychiatric disorder.
A novel, quantitative analytical method for measuring C-reactive protein (CRP) levels in human serum has been developed based on the catalytic activity of gold nanoparticles (GNPs) and luminol-H(2)O(2) chemiluminescence (CL). The CL intensity in the presence of CRP and its ligand, O-phosphorylethanolamine (PEA), was greatly enhanced due to the aggregation of GNPs after the addition of 0.5M NaCl. Any pretreatment steps, such as covalent functionalization of GNPs, addition of antibodies, or labeling of CRP, were not needed for CL detection. The CL enhancement was linearly proportional to CRP concentration in the range of 1.88 fM to 1.925 pM. The detection limit of CRP in serum samples was estimated to be as low as 1.88 fM. The detection sensitivity was increased more than 164 times of magnitude over that of the conventional, enzyme-linked immunosorbent assay (ELISA) method. This proposed GNP-based CL detection method offers the advantages of simplicity, rapidity, and sensitivity.
There is insufficient data regarding the differential diagnosis and the prognostic value of significantly elevated serum levels of C-reactive protein (CRP) in hospitalized medical patients.
A retrospective review of medical charts of patients admitted to a tertiary hospital's Internal Medicine ward during a period of 1 year who had at least one CRP serum level measurement of 200mg/L or more.
Overall, 341 patients with a mean age of 69.8+/-1.0 years were included in the study. Acute infection was the most prevalent diagnosis (n=293; 85.9%) with community-acquired pneumonia being the most common acute infection (n=115; 33.7%). Non-infectious conditions accounted for 9.1% (n=31) of the diagnoses and included mainly malignant metastatic diseases (n=19; 5.6%). Overall, 70 (20.5%) patients died within 30 days of admission. Age and active malignancy, with metastasis or without metastasis, were independently associated with 30-day mortality.
Significantly elevated CRP serum levels are associated with bacterial infections, malignant diseases, and very high rates of 30-day mortality in hospitalized medical patients.
Posttraumatic stress disorder (PTSD) has been associated with several somatic diseases, and low-grade inflammation may be one psychobiological mechanism mediating this relationship. We assessed the association between PTSD and elevated serum levels of C-reactive protein (CRP; >3mg/L) in a large general population sample.
About 3049 adults living in the community were included in the present study. CRP, lipoproteins and triglycerides were determined. Participants were also examined with regard to blood pressure, body mass index (BMI), physical activity, comorbid somatic diseases, medication, daily alcohol intake, and depression.
PTSD was diagnosed in 55 participants (1.8%), and low-grade inflammation (i.e. CRP >3mg/L) was found in 701 subjects (23.0%). PTSD positive participants had significantly higher odds for elevated CRP values than those without PTSD (OR=2.27; 95% CI: 1.32-3.93). Even after adjusting for sex, age, other sociodemographic factors, BMI, blood pressure, lipoproteins and triglycerides, physical activity, comorbid somatic diseases, daily alcohol intake, and trauma exposure, there were almost twofold higher odds for elevated CRP levels in participants with PTSD compared to those without PTSD (OR=1.87; 95% CI: 1.05-3.35).
Our findings suggest a close relationship between PTSD and low-grade inflammation possibly representing one psychobiological pathway from PTSD to poor physical health, particularly with respect to cardiovascular and pulmonary disease as well as diabetes.
C-reactive protein (CRP) was identified in 1930 and was subsequently considered to be an "acute phase protein," an early indicator of infectious or inflammatory conditions. Since its discovery, CRP has been studied as a screening device for inflammation, a marker for disease activity, and as a diagnostic adjunct. Improved methods of quantifying CRP have led to increased application to clinical medicine. In the emergency department (ED), CRP must be interpreted in the clinical context; no single value can be used to rule in or rule out a specific diagnosis. We conclude that CRP has limited utility in the ED. It may be a useful adjunct to serial examinations in equivocal presentations of appendicitis in those centers without ready access to computed tomography (CT) scan. It may be elevated with complications or treatment failures in patients with pneumonia, pancreatitis, pelvic inflammatory disease (PID), and urinary tract infections. In patients with meningitis, neonatal sepsis, and occult bacteremia, CRP is usually elevated. However, CRP has no role in diagnosing these clinical entities, and a normal CRP level should never delay antibiotic coverage.
We compared six inflammatory mediators (C-reactive protein (CRP), interleukin-6 (IL-6), soluble tumour necrosis factor receptors (p55 and p75) and soluble adhesion molecules (ICAM-1, E-selectin)) as early diagnostic tests for neonatal sepsis, and studied the possible benefit of combining parameters. Blood samples were obtained from 166 consecutively admitted neonates, who were suspected to suffer from infection within the first week of life. Neonates were retrospectively classified as infected (sepsis, clinical sepsis or pneumonia), possibly infected, or non-infected. Twenty-four infected neonates had higher serum levels of all six mediators (all P < 0.05), and 18 possibly infected neonates had higher levels of CRP, IL-6, ICAM-1 and E-selectin (all P < 0.05), than neonates without infection (n = 124). Receiver operator characteristic plots showed that CRP was the single best diagnostic test. Multiple logistic regression modelling, including various combinations of two to six mediators, consistently showed that IL-6, in addition to CRP, predicted sepsis. With infected and possibly infected neonates as the reference standard, a combined test of CRP > or = 10 mg/l and/or IL-6 > or = 20 pg/ml had a sensitivity of 85%, specificity of 62%, and negative likelihood ratio of 0.24. Using infected neonates as reference standard alone, and including possibly infected as controls, sensitivity increased to 96%, whereas specificity decreased to 58%; a negative test result (CRP < 10 mg/l and IL-6 < 20 pg/ml) ruled out sepsis with high certainty (likelihood ratio = 0.07). CRP performed best as a diagnostic test for neonatal sepsis. Diagnostic accuracy was further improved by combining CRP and IL-6, whereas the other parameters (p55, p75, ICAM-1 and E-selectin) added no further diagnostic information.
C-reactive protein (CRP) is a positive, acute-phase protein. Plasma levels rise dramatically in response to tissue injury or inflammation and fall rapidly after recovery or treatment. Antibody-based human CRP test systems do not readily detect CRP from other animals due to the species specificity of antibodies directed against human CRP. Thus, generic systems for CRP detection, based solely on the interaction between CRP and phosphocholine (PC), have been developed. PC-bovine serum albumin (PC-BSA) conjugates were produced and either labeled with horseradish peroxidase to facilitate CRP detection in a CRP enzyme-linked sorbent assay (ELSA) or coupled to carboxy-modified microspheres to facilitate the nonenzymatic, turbidimetric detection of CRP. The CRP-ELSA is a competitive assay, where the total assay time is 45 min, the assay sensitivity is 1.06 mg/L CRP, and the dynamic range of the assay is 0-500 mg/L. When PC-BSA conjugate is covalently coupled to carboxylated microspheres, agglutination occurs in the presence of CRP, the extent of which depends on the quantity of CRP present in the sample. Total assay time is 5 min with a dynamic range of 25-500 mg/L. Both assay formats are capable of accurately detecting human CRP and the CRP-ELSA can detect canine CRP as a disease state indicator.
Depression has been related to a higher risk of developing coronary heart disease, but the mechanism that accounts for this association is unclear. Because atherosclerosis is an inflammatory process, depression could increase the risk of coronary heart disease by inducing or promoting inflammation. The objective of the present study was to investigate the association between history of major depressive episode and presence of low-grade systemic inflammation as measured by serum C-reactive protein (CRP).
We analyzed data from the Third National Health and Nutrition Examination Survey, a representative sample of the US population from 1988 to 1994. Participants included a total of 6149 individuals aged 17 to 39 years who were free of cardiovascular diseases and chronic inflammatory conditions. The main predictor variable of interest was lifetime history of a major depressive episode as assessed by means of the Diagnostic Interview Schedule. The main outcome variable was the presence or absence of an elevated CRP level (> or =22 mg/dl).
Among men, history of a major depressive episode was associated with elevated CRP, particularly for recent episodes (up to 6 months before assessment). In multivariate analyses, men with a history of major depressive episode had 2.77 times higher odds of elevated CRP compared with never-depressed men (95% confidence interval, 1.43-5.26). The adjusted odds ratio was 3.81, 3.98, 1.51, and 1.52 for men who had their last major depressive episode less than 1 month before, 1 to 6 months before, 7 to 12 months before, and more than 12 months before assessment, respectively (p for trend =.004). In women, a comparable association between depression and CRP was quite weak and not significant.
A recent history of major depressive episode is strongly associated with elevated CRP in men aged 17 to 39. In this group, low-grade systemic inflammation could represent a mechanism linking depression to cardiovascular risk.
Inflammation is a major factor in atherothrombotic disease. Levels of high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation and a mediator of atherothrombotic disease, have been shown to correlate with cardiovascular disease risk. Recent findings in 27,939 healthy women in the Women's Health Study indicate that hs-CRP (1) is a stronger predictor of risk than low-density lipoprotein (LDL) cholesterol, (2) predicts elevated risk in subjects without overt hyperlipidemia, and (3) adds prognostic information to risk scoring and LDL cholesterol categories. Other data from this cohort show that hs-CRP level adds prognostic information to the diagnosis of the metabolic syndrome. Taken together with other data in men on the association of hs-CRP with vascular risk, a strong argument is provided for screening in the primary prevention population. With regard to potential treatment, statins have been found to reduce hs-CRP levels, and data from statin treatment trials raise the possibility that subjects with elevated hs-CRP levels may derive greater benefit from treatment than do patients without elevated hs-CRP. The Justification for the Use of Statins in Primary Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial is planned to examine the effects of rosuvastatin treatment in preventing cardiovascular events in 15,000 healthy subjects with elevated hs-CRP levels in the absence of overt hyperlipidemia.
High-sensitivity C-reactive protein (hsCRP) is a marker of inflammation that predicts incident myocardial infarction, stroke, peripheral arterial disease, and sudden cardiac death among healthy individuals with no history of cardiovascular disease, and recurrent events and death in patients with acute or stable coronary syndromes. hsCRP confers additional prognostic value at all levels of cholesterol, Framingham coronary risk score, severity of the metabolic syndrome, and blood pressure, and in those with and without subclinical atherosclerosis. hsCRP levels of less than 1, 1 to 3, and greater than 3 mg/L are associated with lower, moderate, and higher cardiovascular risks, respectively. This article summarizes epidemiologic data on the relation between CRP and atherothrombotic disease and provides clinical guidelines for hsCRP screening in cardiovascular risk assessment.
In this paper, we report the novel electrical measurement for the label-free detection of C-reactive protein (CRP) using resonant frequency shift in the monolithic thin film cantilever of micromachined Pb(Zr0.52Ti0.48)O3 (PZT) which was fabricated with the composition of SiO2/Ta/Pt/PZT/Pt/SiO2 on silicon nitride (SiNx) supporting layer for the dual purpose of electrical self-excitation and sensing. The specific binding characteristics of CRP antigen to its antibody, which is immobilized with Calixcrown SAMs on Au surface deposited on microcantilever, is determined in high sensitivity to the nanogram level per milliliter by measuring the resonant frequency shift. The nanomechanical PZT cantilever turns out a robust platform for the highly specific antigen-antibody interaction and provides with the novel tool for qualification and quantification of biomolecules without any sample labeling and bulky optical apparatus.
Atherosclerotic cardiovascular disease, osteopenia, and pulmonary dysfunction are the serious health problems, and several experimental studies have suggested that inflammation has a role in them. The present study was conducted to evaluate the usefulness of the plasma CRP is as a common marker for detecting these diseases in the general population in their subclinical stages. In a cross-sectional study, we measured the pulse wave velocity (PWV), quantitative osteo-sono-assessment index (OSI), pulmonary functions, and the plasma level of C-reactive protein (CRP) in 7283 consecutive healthy subjects (age 50+/-11 years). The PWV was higher and the OSI and pulmonary function parameters were below normal in subjects with an elevated CRP level (> or =0.2 mg/dl) than in subjects with a CRP level within the normal range. We divided the subjects into quartiles for each of these parameters and found that the first quartiles represented patients with subclinical states of the aforementioned abnormal conditions. Logistic regression analysis demonstrated that the odds ratios of an elevated CRP level were individually significant in subjects with an elevated CRP level for each abnormality in women and for abnormal PWV and pulmonary dysfunction in men. In conclusion, in addition to being a marker of elevated atherosclerotic cardiovascular risk, elevated plasma CRP seems to be a marker of the early stages of osteopenia and pulmonary dysfunction in healthy subjects.
This study sought to investigate the relationship between multiple plaque ruptures, C-reactive protein (CRP), and clinical prognosis in acute myocardial infarction (AMI).
Several studies have demonstrated that ruptured or vulnerable plaques exist not only at the culprit lesion but also in the whole coronary artery in some acute coronary syndrome (ACS) patients. Recent studies have reported that a ruptured plaque at the culprit lesion is associated with elevated CRP, which indicates a poor prognosis in patients with ACS.
We performed intravascular ultrasound in 45 infarct-related arteries and another 84 major coronary arteries in 45 first AMI patients.
Plaque rupture was observed in 21 patients (47%) at the culprit site. Intravascular ultrasound revealed 17 additional plaque ruptures at remote sites in 11 patients (24%). Patients with multiple risk factors were more frequently found in our multiple-plaque rupture patients compared with single-plaque rupture or nonrupture patients (82% vs. 40% vs. 29%, p = 0.01). High-sensitive CRP levels had a positive correlation with the number of plaque ruptures (p < 0.01). All culprit lesions were successfully treated by percutaneous coronary intervention. Patients with multiple plaque rupture showed significantly poor prognosis compared with others (p = 0.01).
Multiple plaque rupture is associated with systemic inflammation, and patients with multiple plaque rupture can be expected to show a poor prognosis. Our results suggest that AMI treatment should focus not only on stabilization of the culprit site but also a systemic approach to systemic stabilization of the arteries.
C-reactive protein (CRP) is the prototypical acute phase serum protein, rising rapidly in response to inflammation. CRP binds to phosphocholine (PC) and related molecules on microorganisms and plays an important role in host defense. However, a more important role may be the binding of CRP to PC in damaged membranes. CRP increases clearance of apoptotic cells, binds to nuclear antigens and by masking autoantigens from the immune system or enhancing their clearance, CRP may prevent autoimmunity. CRP binds to both the stimulatory receptors, FcgammaRI and FcgammaRIIa, increasing phagocytosis and the release of inflammatory cytokines; and to the inhibitory receptor, FcgammaRIIb, blocking activating signals. We have shown that, in two animal models of systemic lupus erythematosus (SLE), the (NZB x NZW)F1 mouse and the MRL/lpr mouse, a single injection of CRP before onset of proteinuria delayed disease development and late treatment reversed proteinuria. Thus, in these models, CRP plays an anti-inflammatory role.
In this work, the influence of KOH activation on the surface chemistry of activated carbons (ACs) synthesized from polystyrene-based cation exchangeable resin (PSI) has been investigated. The surface chemistry of ACs has been characterized by using Fourier transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), pH measurement, and Boehm's titration method. As a result, PSI can be successfully converted into ACs with high porosities. The total oxygen content on the ACs studied increases with increasing the KOH-to-PSI ratio. FT-IR and XPS analyses show that the resulting carbons possess a number of oxygen surface functional groups, such as carbonyl, quinone, phenol, ether, and carboxylic acid groups. The highest oxygen content and acid value are observed at a KOH-to-PSI ratio of 4 (KPS-4). However, its pH and surface basicity are higher than those of a KOH-to-PSI ratio of 2 (KPS-2), indicating the formation of basic species, such as quinone and pyrone groups. Although the oxygen-containing groups with basic character exist in the resulting carbons, all the samples are still acidic in character.