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A simple, low-cost instrument for electrochemiluminescence immunoassays based on a Raspberry Pi and screen-printed electrodes
Abstract
A powerful, yet low-cost and semi-portable electrochemiluminescence (ECL) biosensing device is described. It is constructed around a Raspberry Pi single-board computer, which serves as the controller and user interface. The Pi is interfaced with an expansion board that controls the potential applied to a disposable screen-printed electrode and facilitates data acquisition from a photomultiplier tube (PMT), which detects the ECL emission from the sensor surface. As proof-of-concept, we demonstrate that this arrangement can quantitate tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)3]²⁺]) with an estimated limit of detection (LOD) of 20 pM, and C-reactive protein with an LOD of 50 fg mL⁻¹. The analytical performance of the Raspberry Pi-based setup is comparable to a conventional ECL configuration (computer, potentiostat and photodetector). The Raspberry Pi-based setup can replace a conventional ECL setup, at a fraction of the cost, without sacrificing sensitivity or versatility. The combination of a single-board computer and a sensitive light detector represents a significant step towards translating ECL instruments into mobile, point-of-care diagnostic platforms.
... Finally, to detect the emitted ECL signal, techniques such as the photomultiplier tube (PMT), charge-coupled device (CCD), and electrochemical luminescence imaging (ECLI) were employed. In recent times, newly adopted technologies such as mobile phones and CMOS camera-integrated Raspberry Pi have also been utilized for ECL signal detection [28][29][30]. ...
A novel, portable deep learning-assisted smartphone-based electrochemiluminescence (ECL) cost-effective (~10$) sensing platform was developed and used for selective detection of lactate. Low-cost, fast prototyping screen printing and wax printing methods with paper-based substrate were used to fabricate miniaturized single-pair electrode ECL platforms. The lab-made 3D-printed portable black box served as a reaction chamber. This portable platform was integrated with a smartphone and a buck-boost converter, eliminating the need for expensive CCD cameras, photomultiplier tubes, and bulky power supplies. This advancement makes this platform ideal for point-of-care testing applications. Foremost, the integration of a deep learning approach served to enhance not just the accuracy of the ECL sensors, but also to expedite the diagnostic procedure. The deep learning models were trained (3600 ECL images) and tested (900 ECL images) using ECL images obtained from experimentation. Herein, for user convenience, an Android application with a graphical user interface was developed. This app performs several tasks, which include capturing real-time images, cropping them, and predicting the concentration of required bioanalytes through deep learning. The device’s capability to work in a real environment was tested by performing lactate sensing. The fabricated ECL device shows a good liner range (from 50 µM to 2000 µM) with an acceptable limit of detection value of 5.14 µM. Finally, various rigorous analyses, including stability, reproducibility, and unknown sample analysis, were conducted to check device durability and stability. Therefore, the developed platform becomes versatile and applicable across various domains by harnessing deep learning as a cutting-edge technology and integrating it with a smartphone.
... In our project, we employed the Raspberry Pi 4.0 as the hardware platform for our smart irrigation system. The Raspberry Pi 4.0, a powerful single-board computer, offered ample computing power and various connectivity options, making it an ideal choice for IoT applications [26]. By utilising Raspberry Pi 4.0, we were able to run Node-RED and other necessary software components to handle data acquisition, processing, decision-making, and irrigation system control. ...
Smart irrigation systems powered by IoT technology are vital in agriculture. Traditional methods often harm plant health and wastewater. Conversely, IoT-driven smart irrigation enhances water management, boosts crop yield, and supports sustainable farming. It uses sensors, data analysis, and automation to gather and analyse real-time data for informed decisions and real-time control. The hardware comprises a central unit using Raspberry Pi and sensors measuring Temperature, Humidity, and soil moisture. Node-red manages data flow and decision-making by incorporating sensor data and external weather information. It links with the Favoriot platform for seamless data streaming, offering cloud storage and analysis. A predefined set of thresholds for soil moisture, humidity, and Temperature guides irrigation decisions. This system provides precise irrigation assessments, customization, and secure cloud storage. By optimizing water usage, enhancing crop health, and enabling remote monitoring and control, it promotes sustainable water management in agriculture.
... Considering the quantum efficiency (QE) of the sCMOS detector (> 95% at 610 nm) and the photon collection efficiency obtained from the Eq. 1 (η, 19.7 %), it was calculated that the sCMOS detector converts ~18.7 % of photons generated on the electrode into electrons. In the literature, there are plenty of reported miniaturized ECL systems mainly based on smartphone cameras (CMOS) [30][31][32][33][34][35][36][37] , photo-diodes 29,38 , or photomultiplier tubes (PMT) [39][40][41][42][43] . The main limitations of the smartphone cameras are the small light sensitive area and aperture, which limit the applications where ultra-low ECL signals are generated 39,44,45 . ...
Traumatic brain injuries (TBI) are typically acquired when a sudden violent event causes damage to the brain tissue. A high percentage (70-85%) of all TBI patients are suffering from mild TBI (mTBI), which is often difficult to detect and diagnose with standard imaging tools (MRI, CT scan) due to the absence of significant lesions and specific symptoms. Recent studies suggest that a screening test based on the measurement of a protein biomarker panel directly from a patient's blood can facilitate mTBI diagnosis. Herein, we report a novel prototype system designed as a precursor of a future hand-held point-of-care (POC) diagnostic device for the simultaneous multi-biomarker sensing, employing a microarray-type spatially resolved electrochemiluminescence immunoassay (SR-ECLIA). The small tabletop prototype consists of a screen-printed electrode compartment to conduct multi-analyte ECL sandwich assays, a potentiostat module and a light collection module, all integrated into a compact 3D-printed housing (18.2 x 16.5 x 5.0 cm), as well as an sCMOS detector. Based on this design concept, further miniaturization, system integration, performance optimization and clinical evaluation shall pave the way towards the development of a portable instrument for use at the site of accident and healthcare. To demonstrate the system's feasibility, current performance and efficiency, the simultaneous detection of three mTBI biomarkers (GFAP, h-FABP, S100β) in 50% serum was achieved in the upper pg mL-1 range. The proposed device is amenable to the detection of other biomarker panels and thus could open new medical diagnostic avenues for sensitive multi-analyte measurements with low-volume biological sample requirements.
... Based on this, a linear range of 100 fg/mL to 1000 pg/mL with a LOD of 53 fg/mL was reached. Nevertheless, expensive instruments with considerable size including photomultiplier tube (PMT) and optic fiber spectrophotometer are required for ECL measurements [26][27][28][29][30]. That means the point-of-care testing (POCT) of H-FABP using ECL methods is still a challenge [31][32][33][34][35][36]. ...
Heart-type fatty acid binding protein (H-FABP) is an early biomarker for acute myocardial infarction. The concentration of H-FABP in circulation sharply increases during myocardial injury. Therefore, fast and accurate detection of H-FABP is of vital significance. In this study, we developed an electrochemiluminescence device integrated with microfluidic chip (designed as m-ECL device) for on-site detection of H-FABP. The m-ECL device is consisted of a microfluidic chip that enable easy liquid handling as well as an integrated electronic system for voltage supply and photon detection. A sandwich-type ECL immunoassay strategy was employed for H-FABP detection by using Ru (bpy)32+ loaded mesoporous silica nanoparticles as ECL probes. This device can directly detect H-FABP in human serum without any pre-treatment, with a wide linear range of 1-100 ng/mL and a low limit of detection of 0.72 ng/mL. The clinical usability of this device was evaluated using clinical serum samples from patients. The results obtained from m-ECL device are well matched with those obtained from ELISA assays. We believe this m-ECL device has extensive application prospects for point-of-care testing of acute myocardial infarction.
... Experimental work in chemistry education was no exception, and there are many articles describing SBC-based devices that were built to support laboratory instruction [2][3][4][5]. The establishment of the Raspberry Pi foundation, as a charity promoting the educational value of their products, helped spread the idea of using a small, inexpensive, connected computer in various scientific and educational setups [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Several authors have researched and recognized the potential of using SBCs in chemistry-driven integrated Science, Technology, Engineering, and Mathematics (STEM) education. ...
We describe a master’s level chemistry education course that was designed to support STEM education by strengthening the E component with an engineering approach. Engineering approach is a method of conducting projects systematically similar to professional engineers. In the course, the future chemistry teachers were given the task of building a measurement instrument using a single-board computer (SBC). In addition to course description, we present a pilot study, the aim of which was to explore the opportunities and challenges the engineering approach initiates with pre-service chemistry teachers trying to accomplish a SBC-based open engineering project. The study employed a qualitative research approach, using the course as the data collection platform. The collected data was analyzed using an inductive content analysis. The data analysis shows that an open SBC project is a good platform for learning and teaching future chemistry teachers about chemistry-driven STEM education, but it is very challenging to conduct. The main conclusion is that the engineering approach is a practical solution for strengthening the engineering in STEM education. To generalize these findings to a wider context, we suggest further research to improve the course using this study’s results and re-evaluate the approach in a new instance of the course.
... [6,8,[39][40][41][42][43] To resolve this challenge, recent advances have exploited the feasibility of using smartphone camera as photodetector for ECL measurements. [44][45][46][47][48] For example, the Hogan group has demonstrated that the smartphone camera is suitable for ECL signal readout in the paper-based microfluidic sensing. [49] The Liu group has also reported that smartphone based ECL system can image fingermarks. ...
Electrochemiluminescence (ECL) is a powerful electroanalytical transduction technique in biosensing and clinic immunodiagnostics, however its practical applications for point-of-care testing (POCT) are rather limited because of the requirements of large sized electrochemical workstation for electrical stimulation and photomultiplier tube for light detection. Herein we report a fully integrated and handheld ECL device consisting of a flexible printed circuit board based electrochemical module, a silicon photomultiplier and a Bluetooth enabled smartphone with an Android application interface. The device together with an electrochemical cell and light-tight box has a dimension of 17 cm × 9 cm × 9 cm, thus being suitable for on-site detection and POCT. To demonstrate the performance and efficiency of this device, we implemented the detection of dopamine (DA), using the indium tin oxide glass electrode coated with antifouling silica nanoporous membrane as the working electrode for improving the sensing stability and sensitivity. A fast response to DA with a wide linear range of 5 nM ∼ 20 μM and an ultralow detection limit of 3.5 nM were obtained with the handheld ECL device. These attractive features allow the device to satisfy the basic requirements for POCT of DA in complex bio-samples, including urine and rat brain homogenate. This work provides a novel strategy for ECL based POCT, showing the potential of broad utility in resource-limited settings where there is a lack of medical facilities.
Diagnostics are essential components of the healthcare and medical industry. Their uses range from initial prognosis to accurate identification to continuous monitoring of the effectiveness of interventions. However, many diagnostics have a high cost, requiring specialist training and bulky instruments, and being time consuming to use.
Developments in detection technology and manufacturing have created a family of diagnostics that are:
Compiled from recent findings by leading global researchers, this book is a comprehensive reference for researchers looking to develop low-cost diagnostics for societal impact as well as health professionals interested in learning more about this technology. Broken down into five sections, coverage includes different techniques such as fluorescent probes, electrochemiluminescence and electroanalytical; fabrication of different types of biosensors; real-world applications; nanomaterial-based biosensors; and, finally, diagnostics based on 3D-printing for the diagnosis of viral infections and more.
Replacing existing conventional devices minimizes limitations and increases access. There is no need for you to continue to use the second best, read about how you can make an impact with new diagnostic tools that will save you time and money.
In this study, a portable electrochemiluminescence (ECL) imaging system based on Raspberry Pi was developed for the instant detection of melamine. The system employed a lithium battery as the excitation source and Ru(bpy)3²⁺/TPA as the reaction system. A homemade 3D-printed black box served as a reaction chamber for the ECL reaction. ECL images were captured by a camera and subsequently classified by the MobileNet model. Over 500 images obtained from the experiment were used as a self-built dataset to train the neural network model. As the core processor, Raspberry Pi was not only used to control the camera, but also to perform Image enhancement and color analysis. The experimental results were further validated using image processing algorithms. The system demonstrated highly sensitive detection of melamine under optimal conditions, with a linear fit curve in the range of 10⁻⁸–10⁻³ M and a detection limit of 3.54 nM. In conclusion, this system holds great potential for the instant detection of melamine.
Electrochemical biosensors have the potential to provide rapid and inexpensive diagnostics while moving clinical testing from centralized labs to point-of-care (POC) applications. Conductive materials functionalized with bioreceptors that remain stable and functional for measurements in real-world conditions are essential for the fabrication of electrochemical biosensors, and carbon-based nanomaterials provide the electrical, chemical, structural, and mechanical features that make them suitable for POC devices. This review details the most recent developments in the use of carbon-based nanostructures, with a focus on one-dimensional carbon nanotubes, two-dimensional graphene, and graphene oxide, their interface with biological receptors, deposition on portable, flexible, and wearable substrates, and integration on low-cost platforms for detection of clinical biomarkers. The large-scale manufacturing and implementation of microneedles as implantable and electronic tattoos as wearable devices for on-skin diagnostics, and lab-on-mouth platforms as well as the interface with mobile technologies and their potential implementation for remote POC monitoring and decentralized healthcare through cloud processing and the internet of things (IoT) are discussed with examples of applications. The review concludes with an overview of the regulatory perspectives and future trends, challenges, and opportunities for commercialization and translation of these technologies from the research lab to practice, as useful diagnostic tools for remote monitoring of patient health conditions.
Point-of-care testing (POCT) is also known as near-patient or on-site testing. Because of its speediness, high efficiency, low cost, and excellent convenience, POCT has been widely used in clinical diagnosis, infectious disease surveillance, drug screening, and food quality monitoring. Electrochemiluminescence (ECL) is a powerful transduction technique in biosensing and immunodiagnostics, thus attracting more and more research attention in POCT applications. In this article, we present an overview of various ECL-POCT devices that have been developed so far. The article will begin with a short introduction of different types of ECL-POCT devices. Then we shall discuss the categories, detection strategies, and application scenarios of current ECL-POCT devices. The article finally ends up with a short conclusion and perspectives. We hope this article is helpful for understanding, constructing, and designing ECL devices for POCT.
Phenolic compounds such as vanillic and p‐coumaric acids are pollutants of major concern in the agro‐industrial processing, thereby their effective detection in the industrial environment is essential to reduce exposure. Herein, we present the quenching effect of these compounds on the electrochemiluminescence (ECL) of the Ru(bpy)32+/TPrA (TPrA=tri‐n‐propylamine) system at a disposable screen‐printed carbon electrode. Transient ECL profiles are obtained from multiple video frames following 1.2 V application by a smartphone‐based ECL sensor. A wide range of detection was achieved using the sensor with limit of detection of 0.26 μM and 0.68 μM for vanillic and p‐coumaric acids, respectively. The estimated quenching constants determined that the quenching efficiency of vanillic acid is at least two‐fold that of p‐coumaric acid under the current detection conditions. The present ECL quenching approach provided an effective method to detect phenolic compounds using a low‐cost, portable smartphone‐based ECL sensor. The efficient ECL quenching of the Ru(bpy)32+/TPrA system by phenolic compounds using a low‐cost portable ECL sensor may provide a new approach in the industrial environments for the monitoring of these environmentally critical analytes. A wide range of detection was achieved using the sensor with LOD of 0.26 μM and 0.68 μM for vanillic and p‐coumaric acids, respectively. The estimated quenching constants determined the quenching efficiency of vanillic and p‐coumaric acids under the current detection conditions.
Vitamin B12 plays a very important role in human body and its deficiency can be detrimental to the production of red blood cells, anemia, memory loss, low immunity to infection, and permanent and severe damage in the nervous system and brain. In the present work, vitamin B12 sensing has been accomplished using two Electrochemiluminescence (ECL) platforms, one with Bipolar Electrode (BPE), while the second one Single Electrode (SE). The electrodes were fabricated on polyimide (PI) substrate by creating optimized Laser-Induced Graphene (LIG). With optimized speed and power of CO2 Laser, non-conducting portion of PI gets converted into conducting zone (electrodes) for ECL imaging. A 3D-printed miniaturized portable system was developed to detect and monitor the ECL signals. Android smartphone was effectively used to provide dual functions such as to drive the DC to DC buck-boost converter and to capture the ECL images. The sensing of vitamin B12 was accomplished in the linear range 0.5–700 nM and 0.5–1000 nM with a limit of detection (LOD) 0.107 nM (R2 = 0.98, n = 3) and 0.094 nM (R2 = 0.977, n = 3), respectively, for BPE and SE-based ECL platforms correspondingly. Therefore, proposed ECL platforms can be selectively used in various domains such as point of care testing (POCT) and biomedical applications.
Antibiotic resistance is a worldwide problem aggravated by the overuse of prophylactic antibiotic therapies and lack of real-time biosensing equipment to differentiate viral from bacterial infections at the Point of Care (POC), particularly in rural areas with limited access to clinical laboratory facilities. As recent studies reveal the potential of C-Reactive Protein (CRP) and other acute phase biomarkers to achieve early determination of etiology in acute febrile illness, novel biosensing equipment become a plausible approach in preventing the unnecessary prescription of antibiotics. A low-cost experimental platform was engineered to measure CRP concentrations in 50 μL samples of buffer and enriched plasma, using label-free antigenic probes, legacy electrochemical methods and open-source hardware. The prototype presents a portable, cost-effective device for use at the POC with a simplified user interface that can be used wirelessly by healthcare professionals using a mobile phone or laptop. Based on the measured CRP levels, the device suggests if the acute febrile episode is likely to be of bacterial etiology.
The demand for wearable and point-of-care devices has led to an increase in electrochemical sensor development to measure an ever-increasing array of biological molecules. In order to move from the benchtop to truly portable devices, the development of new biosensors requires miniaturized instrumentation capable of making highly sensitive amperometric measurements. To meet this demand, we have developed KickStat, a miniaturized potentiostat that combines the small size of the integrated Texas Instruments LMP91000 potentiostat chip (Texas Instruments, Dallas, TX, USA) with the processing power of the ARM Cortex-M0+ SAMD21 microcontroller (Microchip Technology, Chandler, AZ, USA) on a custom-designed 21.6 mm by 20.3 mm circuit board. By incorporating onboard signal processing via the SAMD21, we achieve 1 mV voltage increment resolution and an instrumental limit of detection of 4.5 nA in a coin-sized form factor. This elegant engineering solution allows for high-resolution electrochemical analysis without requiring extensive circuitry. We measured the faradaic current of an anti-cocaine aptamer using cyclic voltammetry and square wave voltammetry and demonstrated that KickStat’s response was within 0.6% of a high-end benchtop potentiostat. To further support others in electrochemical biosensors development, we have made KickStat’s design and firmware available in an online GitHub repository.
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.
Bipolar electrochemistry allows for facile arraying of tens to thousands of electrochemical sensors that can be controlled by a single pair of driving electrodes. While bipolar electrodes (BPEs) have been applied to many sensing motifs, their sensitivity and specificity are limited by the lack of diversity in voltammetric methods that have been developed for these wireless electrodes. In this study, electrochemiluminescence (ECL) from the co‐oxidation of Ru(bpy) 3 2+ and tripropylamine (TPA) is evaluated as a reporting reaction for alternating current voltammetry (ACV) on a BPE at frequencies of 1.0 Hz and 5.0 Hz. We observe sinusoidal alternating luminescence that follows a similar trend to that of the simultaneously monitored current – a plot of the amplitude versus potential approximates a bell‐shaped curve. Notably, the luminescent response to the current is detected with a smartphone, which underscores the portability of this method. The fidelity of the transduced signal is determined both in a traditional 3‐electrode configuration and at a BPE. These experimental results indicate that the alternating luminescence follows the current sufficiently for quantitative sensing but is diminished at higher frequencies and peaks at a shifted potential. These results are significant because they demonstrate the potential for application of ACV at BPE arrays for multiplexed point‐of‐need sensors and provide guidance for the selection of reporting reactions in this context.
In this work, a compact, mobile phone-based ECL sensor apparatus was developed using the phone cameras, screen-printed electrodes (SPE), and mobile app for dopamine detection. Methods of DC voltage application for ECL reaction were comprehensively studied from the mobile phone itself or external power. Under optimized sensing conditions, with disposable carbon SPE and 20 mM coreactant tri-n-propylamine (TPrA), acceptable repeatability and reproducibility were achieved in terms of relative standard deviation (RSD) of intra- and interassays, which were 6.7 and 5.5%, respectively. The biochemical compound dopamine was measured due to its ECL quenching characteristics and its clinical importance. The quenching mechanism of Ru(bpy)3²⁺/TPrA by dopamine was investigated based on the estimation of the constants of the Stern-Volmer equations. The linear range for detectable dopamine concentration was from 1.0 to 50 μM (R² = 0.982). As the developed mobile phone-based ECL sensor is simple, small and assembled from low-cost components, it offers new opportunities for the development of inexpensive analytical methods and compact sensors.
Translation of the highly promising electrogenerated chemiluminescence (ECL) properties of Ir(III) complexes (with tri-n-propylamine (TPrA) as a co-reactant) into a new generation of ECL labels for bioassay necessitates the introduction of functionality suitable for bioconjugation. Modification of the ligands, however, can affect not only the photophysical and electrochemical properties of the complex, but also the reaction pathways available to generate light. Through a combined theoretical and experimental study, we reveal the limitations of conventional approaches to the design of electrochemiluminophores and introduce a new class of ECL label, [Ir(C^N)2(pt-TOxT-Sq)]⁺ (where C^N is a range of possible cyclometalating ligands, and pt-TOxT-Sq is a pyridyltriazole ligand with trioxatridecane chain and squarate amide ethyl ester), which outperformed commercial Ir(III) complex labels in two commonly used assay formats. Predicted limits on the redox potentials and emission wavelengths of Ir(III) complexes capable of generating ECL via the dominant pathway applicable in microbead supported ECL assays were experimentally verified by measuring the ECL intensities of the parent luminophores at different applied potentials, and comparing the ECL responses for the corresponding labels under assay conditions. This study provides a framework to tailor ECL labels for specific assay conditions and a fundamental understanding of the ECL pathways that will underpin exploration of new luminophores and co-reactants.
C-reactive protein (CRP) is one of the important indicators of inflammatory response. It plays as an essential role in diseases such as myocardial infarction and atherosclerosis. A simple and effective label-free electrochemiluminescent (ECL) immunosensor for quantitative detection of CRP is reported. The indium tin oxide coated glass was prefunctionalized with the composite of titania nanotubes and platinum nanowires as the sensing matrix. Then the CRP antibody was immobilized on it, hosted the sensing function owing to its specific binding with CRP caused by immune affinity. The characteristics of the fabricated sensor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and electron microscopes. The sensor has the advantages of high sensitivity, good selectivity, good reproducibility and low cost. Under the optimal experimental conditions, the response of ECL signal on obtained sensor has a good linear regression toward the logarithm of CRP quantity within the range from 0.05 ng to 6.25 ng with a detection limit of 0.011 ng. The immunosensor is small, convenient to use, and provides a feasible way for domestically rapid detection of CRP. It has a promising future in the precaution of cardiovascular and other diseases.
Cardiovascular diseases (CVDs) are responsible for a high mortality rate worldwide. One of the most common causes of CVDs is vascular inflammation associated to atherosclerosis. Inflammatory biomarkers are used to assist the detection of CVDs and monitor their evaluation, prognosis and therapy implementation. C-reactive protein (CRP) is an acute phase protein produced after stimulation by pro-inflammatory cytokines. CRP is a biomarker of the inflammatory reaction and an important mediator of atherosclerosis. Given it actively contributes to the development of the atherosclerotic plaque, instability and subsequent clot formation it is also considered a CVD risk factor. Since 2010, the plasma concentration of hsCRP (high sensitivity CRP) has been used as a biomarker for disease prognosis in patients with intermediate risk for CVDs. It could be useful to establish a high concentration limit of hsCRP that can be used by clinicians for diagnosis of acute myocardial infarction, cardio embolic or ischemic stroke, and hypertrophic cardiomyopathy. The end cost/effectiveness of hsCRP screening is still an area of controversy but it is a priority to make the medical community aware of the positive relation between high hsCRP and CVDs to improve median survival and life quality of the patients.
This paper presents a teaching kit that combines the fabrication of a low-cost microcontroller-based potentiostat and a LabVIEW-generated graphical user interface. The potentiostat enables undergraduate-level students to learn electroanalytical techniques and characterize energy conversion devices such as solar cells. The purpose of this teaching module is to make the introduction of electrochemistry accessible to undergraduate laboratories, especially those with limited financial resources and without expertise in electronics or programming. The electronic circuit components for the potentiostat are readily available and easy to assemble. The graphical user interface replaces any programming-based interface, displays data in real time, and interacts with user commands. The software package is a stand-alone executable file that is compatible with any PC and is provided in the Supporting Information. Cyclic voltammetry, linear sweep voltammetry, and chronoamperometry functions are demonstrated with representative electrochemical experiments, and the data obtained are comparable to those obtained with a research-grade potentiostat. This teaching module is user-friendly so that it can be easily adapted into the undergraduate classroom. We make available in the Supporting Information all of the necessary instructions and information, including schematics for the potentiostat, circuit layout, electronic components, case fabrication, step-by-step instructions for assembly, software user interface, and detailed operating instructions.
Native C-reactive protein (nCRP) is a non-specific marker of inflammation being claimed as a bystander in several chronic disorders. Accumulating evidence indicates that nCRP dissociates to and acts primarily as the monomeric conformation (mCRP) at inflammatory loci. This suggests that mCRP may be a superior disease marker with improved specificity and clear causality to the underlying pathogenesis. However, the lack of a feasible assay to quantify mCRP in clinical samples precludes the assessment of that suggestion. Here we report the development of a sandwich ELISA assay for quantification of plasma mCRP using commercially available reagents. Our assay is reproducible and highly conformation-specific showing a reliable detection limit of 1 ng/mL. We further show that mCRP appears to be a better marker than nCRP in several skin-related autoimmune disorders. This assay thus provides a useful tool to examine the clinical significance and utility of mCRP.
Saliva is often neglected as a body fluid of diagnostic or prognostic value, even though generally well accepted by the patients. This is due to lack of a standardized collection procedure. The aim of this study was to identify the ideal saliva collection technique and develop new sensitive methods to detect and analyse markers related to pain in healthy pain-free subjects. Plasma and five different saliva collection approached was evaluated during strictly controlled conditions. Levels of nerve growth factor (NGF), calcitonin gene-related peptide (CGRP) and brain derived neurotropic factor (BDNF) were determined using novel western blotting based technology. Glutamate and substance P (SP) was determined using commercial available methods. Several new isoforms were found for NGF, CGRP and BDNF in saliva. The isoform pattern showed significant variation in both expression and chemiluminescence levels between different collection methods. New sensitive methods to study pain related markers in saliva were developed in this study. Furthermore, we are first to demonstrate a correlation between the Glutamate concentration in stimulated whole saliva and blood. However, the fundamental conclusion drawn is the importance of consistency in the collection method.
The Raspberry Pi Foundation aims to promote the teaching of Computer Science and is inspired by devices such as the ZX81 and Spectrum [1], the first home computers from the 1980s, and government backed in-school devices such as the BBC Acorn [2].[...]
Herein, a new miniaturized analytical instrumentation for electrochemiluminescence (ECL) assays is presented. A photodiode integrated in an ECL cell combined with a potentiostat/galvanostat, all integrated in a one-piece instrument (μSTAT ECL), was developed. In addition, a complementary micro-spectrometer integrated in a similar ECL cell for luminescence spectra recording is also proposed. Both cells are intended to be used with screen-printed electrodes and all the devices are portable and small sized. Their performance was corroborated with two innovative proofs-of-concept that centered on the luminol transduction chemistry: a first time reported ECL assay based on the enzymatic reaction between an indoxyl substrate and the enzyme alkaline phosphatase, and the electrochemiluminescence resonance energy transfer (ECL-RET) process triggered by the electro-oxidized luminol to the acceptor fluorescein. The photodiode system revealed to be more sensitive than the spectrometer device in collecting the light; however, with the latter, it is possible to discriminate different luminescent species according to their maximum wavelength emission, which is extremely useful for carrying out simple and simultaneous ECL multiplex analyzes. The spectrometer device works as an excellent accessory to couple with the μSTAT ECL instrument, complementing the experiments.
Graphical abstract
Schematic representation of the ECL-RET: from luminol–H2O2 system to fluorescein, the micro-spectrometer for the light collection and the 3D representation of the ECL-RET reaction.
This work exploits the high-affinity of recombinant antibodies and low background electrochemiluminescence (ECL) for cardiac-biomarker detection. The developed assay is capable of fg mL-1 detection limits as well as the detection of C-Reactive Protein (CRP) over a clinically relevant range. The assay demonstrated robust reproducibility, selectivity and stability while also highlighting a novel platform for detection of cardiac biomarkers at low concentrations.
There is a growing demand to realize low-cost miniaturized point-of-care testing diagnostic devices capable of performing many analytical assays. To fabricate such devices, three-dimensional printing (3DP) based fabrication technique provides a turnkey approach with remarkable precision and accuracy. Herein, 3DP fabrication technique was successfully utilized to fabricate closed bipolar electrode-based Electrochemiluminescence devices using conductive graphene filament. Further, using these ECL devices, Ru (bpy)3 2+ /TPrA and Luminol/H2 O2 based electrochemistry was leveraged to sense dopamine and choline respectively. For ECL signal capturing, two distinct approaches were used, first a smartphone-based miniaturized platform and the second with a photomultiplier tube (PMT) embedded with the Internet of Things technology. Choline sensing led to a linear range 5 μM to 700 μM and 30 μM to 700 μM with limit of detection (LOD) of 1.25 μM (R2 = 0.98, N = 3) and 3.27 μM (R2 = 0.97, N = 3). Further, dopamine sensing was achieved in a linear range of 0.5 μM to 100 μM with LOD = 2 μM (R2 = 0.99, N = 3) and LOD = 0.33 μM (R2 = 0.98, N = 3). Overall, the fabricated devices have the potential to be utilized effectively in real-time applications such as point-of-care testing.
Miniaturized Electrochemiluminescence (ECL) systems are widely recognized as highly detection, user-friendly and turnkey strategy to develop point-of-care testing (POCT) devices. ECL sensing approach provides numerous advantages over other methods, including high signal-to-noise ratio and measurement with minimal or no background signal. ECL signal can be easily controlled by a small external potential while providing high sensitivity and decreased electrode fouling, resulting in the use of ECL based miniaturized systems for detection and monitoring of different analytes, including DNA and bacteria. In this work, different types of miniaturized ECL systems with various fabrication techniques are reviewed and their application in POCT is thoroughly discussed. Further, such ECL platforms have been summarized based on type of ECL mechanism, electrodes, range of detection and limit of detection. Finally, some of the upcoming technological interventions to make such miniaturized ECL platform amenable for portable and on-field analysis have been discussed.
As an oxidase stress biomarker, 3-nitrotyrosine is closely associated with many cardiovascular diseases. Thus, early diagnosis and real time detection of 3-nitrotyrosine at bedside are highly important. Herein, we developed a handheld electrochemiluminescence (ECL) analysis device, which integrates printed circuit board (PCB) for electrical stimulation and smartphone for optical signals readout. Fast and accurate determination of 3-nitrotyrosine was achieved with Antibody/Ru(dcpy)3²⁺@AuNPs/MoS2 modified Au electrode (Ab/[email protected]/MoS2) for ECL analysis. The linear range of 3-nitrotyrosine detection was from 10⁻⁸ mol/L to 10⁻⁶ mol/L with a detection limit of 8.4×10⁻⁹ mol/L. In addition, an Android application was developed to realize real time analysis of ECL emissions and results readout for detection. To confirm the usage of the device, spiked serum with different concentrations was tested and the results indicated the practical reliability and stability of this device. The operating procedure for ECL analysis in this device is extremely easy and electrical stimulation was adjustable from 0 V to 5 V for general ECL systems. Thus, we believe this handheld device for ECL analysis has extensive prospects for application in Point-of-care testing and health caring.
Rapid screening of pathogenic bacteria contaminated foods is crucial to prevent food poisoning. However, available methods for bacterial detection are still not ready for in-field screening because culture is time-consuming; PCR requires complex DNA extraction and ELISA lacks sensitivity. In this study, a microfluidic biosensor was developed for rapid, sensitive and automatic detection of Salmonella using metal-organic framework (MOF) NH2-MIL-101(Fe) with mimic peroxidase activity to amplify biological signal and Raspberry Pi with self-developed App to analyze color image. First, the target bacteria were separated and concentrated with the immune magnetic nanobeads (MNBs), and labeled with the immune MOFs to form MNB-Salmonella-MOF complexes. Then, the complexes were used to catalyze colorless o-phenylenediamine and H2O2 to produce yellow 2,3-diaminophenazine (DAP). Finally, the image of the catalysate was collected under the narrow-band blue light and analyzed using the Raspberry Pi App to determine the bacterial concentration. The experimental results showed that this biosensor was able to detect Salmonella Typhimurium from 1.5 x10¹ to 1.5 x10⁷ CFU/mL in 1 h with the lower detection limit of 14 CFU/mL. The mean recovery for Salmonella in spiked chicken meats was ∼112%. This biosensor integrating mixing, separation, labelling and detection onto a single microfluidic chip has demonstrated the merits of automatic operation, fast reaction, less reagent and small size, and is promising for in-field detection of foodborne bacteria.
We reported two sensors for METH with synergistical alliance of sensitive electrochemiluminescence (ECL) quantification and specifically immune recognition. These sensors are applicable for point‐of‐care testing when equipped a portable ECL meter with outstanding performance, makes the feasibility of on‐spot analysis. The dual‐way analysis of immunosensors can be carried on, both exhibit unprecedented sensitivity toward METH. Here, AuNPs functioned indium tin oxide (ITO) coated polyethylene terephthalate (PET) is used as the basal electrode, providing excellent ECL background and supporting the sensing matrix. The real sample identification demonstrated the practicability and accuracy which met the requirement of forensic judgement and clinical treatment.
microRNAs (miRNAs) have emerged as important biomarkers for numerous diseases, but their widespread use has been hampered by the lack of point-of-care testing solutions. Herein, we demonstrate a sensitive, rapid and portable electrochemiluminescence (ECL) based sensor for miRNA-21 combining a switch-on ECL molecular beacon with magnetic bead based extraction of the miRNA target sequence. Streptavidin coated magnetic beads were functionalised with a hairpin molecular beacon; one stem of the beacon was functionalised with an ECL active label and the opposing stem was functionalised with a quencher. When the target miRNA was present, the hairpin opened, separating the label and quencher, generating an intense ECL signal. The sensor provides a simple and robust strategy for miRNA detection without the need for intercalating labels, reporter probes for detection, added enzymes or hairpin primers for target amplification. The detection limit of the sensor is 500 attomoles of miRNA-21 when using a photomultiplier tube for ECL detection. The potential of the developed sensor for point-of-care applications has been demonstrated by combining the molecular beacon ECL sensor with a portable potentiostat for ECL generation and a mobile phone camera for ECL detection of miRNA-21.
COVID-19 pandemic has affected everyone throughout the world and has resulted in the loss of lives of many
souls. Due to the restless efforts of the researchers working hard day and night, some success has been gained for
the detection of virus. As on date, the traditional polymerized chain reactions (PCR), lateral flow devices (LFID)
and enzyme linked immunosorbent assays (ELISA) are being adapted for the detection of this deadly virus.
However, a more exciting avenue is the detection of certain biomarkers associated with this viral infection which
can be done by simply re-purposing our existing infrastructure. SARS-CoV-2 viral infection triggers various inflammatory, biochemical and hematological biomarkers. Because of the infection route that the virus follows, it
causes significant inflammatory response. As a result, various inflammatory markers have been reported to be
closely associated with this infection such as C-reactive proteins, interleukin-6, procalcitonin and ferritin.
Sensing of these biomarkers can simultaneously help in understanding the illness level of the affected patient.
Also, by monitoring these biomarkers, we can predict the viral infections in those patients who have low SARSCoV-2 RNA and hence are missed by traditional tests. This can give more targets to the researchers and scientists,
working in the area of drug development and provide better prognosis. In this review, we propose to highlight
the conventional as well as the non-conventional methods for the detection of these inflammatory biomarkers
which can act as a single platform of knowledge for the researchers and scientists working for the treatment of
COVID-19.
Early detection of inflammatory mediators including C-reactive protein (CRP) is of great diagnostic importance in many human diseases. CRP elevates very fast in conditions such as tissue injuries, infections, cancers, and renal and cardiovascular diseases. Conventional techniques for detecting CRP are based on antigen-antibody, agglutination, and precipitation reactions. Newer methods based on immunoturbidimetry and immunonephelometry are also time-consuming and relatively expensive. For solving these problems, highly efficient techniques based on CRP-biosensors have been introduced. Here, our aim was to summarize the features of recent biosensors for detection of CRP in biological samples. These include electrochemical (voltammetric and impedimetric), optical (surface plasmon resonance, fluorescence and luminescence), field effect transistor (FET), and quartz crystal microbalance (QCM) biosensors which have been addressed in detail here.
We developed a miniaturized electrochemiluminescence (ECL) instrument coupled with a light‐emitting diode‐based bipolar electrochemical sensor (LED‐BPES). This instrument composes of a microcontroller circuit, a power supply circuit, a potentiostat, an optical detecting circuit, and a communication circuit. The multi‐pixel photon counter (MPPC), which is low‐cost, small‐size, and wide‐range in optical measurements, is chosen as the optical detector. The LED‐BPES composes of a disposable screen‐printed carbon electrode (SPCE) and a surface‐mount red LED. Depended on the closed bipolar electrode (C‐BPE) structure, the LED‐BPES not only avoids the employment of unstable and complex ECL reactions but also offers a cost‐effective alternative for the over‐priced ECL reagents by using a mini‐size commercial LED as the luminescent producer. The combination of MPPC and LED‐BPES helps to set up the simplified and downsized instrument system with low price and high efficiency. The presented instrument coupled with LED‐BPES works excellent in electroactive molecules detection and has great potential in the application of heavy metal ions detection.
Cardiovascular diseases (CVD) are one of the greatest causes of human mortality in the western world, have been associated with hundreds of risk factors and subsequently, places a huge burden on healthcare amenities and the economy. The early appearance of a biochemical marker released into the bloodstream soon after an injury may facilitate early diagnosis and management process. Biomarker detection demand is opened an important way in the biosensor development field. The accurate measurement of serum C-reactive protein (CRP) levels and cardiac troponin I (cTnI) have been given particular attention as a specific marker of inflammation associated with CVD. The electrochemical biosensors along with two key bioreceptors such as antibodies and aptamers simplify the detection and quantification strategies of CVD biomarkers. The prime motive of this review article is to present a comprehensive understanding of the pros and cons of methodologies employed for the electrode construction and sensing approaches for the CRP and cTnI that have been reported. Also reviewing those that are presently being advanced for the sensitive, specific, cost-effective and high-throughput blood analysis of these biomarkers using various nanomaterials-based microfluidic sensing platforms to find ways to improve the performance of biosensors with new design aspects for multiplexing.
In this paper, we show an unprecedented device obtained by coupling a small potentiostat to an electronic micropipette. The minipotentiostat is powered by the micropipette battery and controlled by a smartphone via a Bluetooth wireless connection. A set of 3 electrodes is inserted into the tip of the micropipette with the aid of an adapter that allows electrochemical measurements to be carried out without affecting the precision and trueness of handling of small volumes of liquid. Studies with the device show significant gains in portability, versatility, agility and for analytical procedures. This approach requires small volume of samples and reagents with the possibility of recovery after analysis. Determination of hydrogen peroxide with the aim for future development of enzymatic biosensors for clinical analysis was shown as an example of application. We consider that the device shown here contributes to a new way to performing electrochemical analysis on site.
For the last few decades, the air and water pollution issues are controlled by various government schemes based on infrastructure and industrial development. The population of people is still growing in accordance with development. So it is impractical one to overcome completely because of continuous monitoring, and data base maintenance is not available. Now days the child and old age peoples are affected mainly by air and water pollutions, when they are admitted in hospitals. The main aim of this project is to concentrate on continuous real time monitoring of air pollution, water pollution, temperature, humidity maintenance in incubator rooms in hospitals and maintain database in cloud using Internet of Things (IoT) for future analysis and remedies are developed based on analysis.
Critical biomarkers of disease are increasingly being detected by point‐of‐care assays. Chemiluminescence (CL) and electrochemiluminescence (ECL) are often used in such assays due to their convenience and that they do not require light sources or other components that could complicate or add cost to the system. Reports of these assays often include readers built on a cellphone platform or constructed from low‐cost components. However, the impact the optical design has on the limit of detection in these systems remains unexamined. Here, we report a theoretical rubric to evaluate different optical designs in terms of maximizing the use of photons emitted from a CL or ECL assay to improve the limit of detection. We demonstrate that the majority of cellphone designs reported in the literature are not optimized, in part due to misunderstandings of the optical tradeoffs in collection systems, and in part due to limitations imposed on the designs arising from the use of a mobile phone with a very small lens aperture. Based on the theoretical rubric we design a new portable reader built using off‐the‐shelf condenser optics, and demonstrate a nearly 10x performance enhancement compared to prior reports on an ECL assays running on a portable chip. This article is protected by copyright. All rights reserved.
We report on the use of boron doped diamond electrodes for the electrochemiluminescence (ECL) of the coreactant peroxydisulfate and the luminophore ruthenium(II)-tris(2,2’-bipyridine). Compared to common electrode materials (i.e. Pt, Au, glassy carbon), boron doped diamond has a large overpotential for the evolution of hydrogen in aqueous electrolyte solutions. This intrinsic feature enables reductive-oxidation ECL with peroxydisulfate to be obtained with-out interference from hydrogen evolution, and with high reproducible signals and stable emission. We investigated the effects of the peroxydisulfate concentration and the pH on the ECL emission to find the optimal conditions for enhancing the signal.
IoT (Internet of Things) is a new paradigm which provides a set of new services for the next wave of technological innovations. IoT applications are nearly limitless while enabling seamless integration of the cyber-world with the physical world. However, despite the enormous efforts of standardization bodies, alliances, industries, researchers and others, there are still numerous problems to deal with in order to reach the full potential of IoT. These issues should be considered from various aspects such as enabling technologies, applications, business models, social and environmental impacts. In focus of this paper are open issues and challenges considered from the technological perspective. Just for clarification, we put in light different visions that stand behind this paradigm in order to facilitate a better understanding of the IoT's features. Furthermore, this exhaustive survey provides insights into the state-of-the-art of IoT enabling and emerging technologies. The most relevant among them are addressed with some details. The main scope is to deliver a comprehensive overview of open issues and challenges to be tackled by future research. We provide some insights into specific emerging ideas in order to facilitate future research. Also, this paper brings order in the existing literature by classifying contributions according to different research topics.
Electrochemiluminescence (ECL) has been considered to have better performance in rapid detection. A novel paper-based ECL biosensing platform for hepatitis B surface antigen (HBsAg) detection was developed based on a simple paper discs, the flexible design of a machine and a circuit of the custom-made ECL device. Through the modified magnetic suspension sandwich immunoassay protocol, rapid and sensitive clinical HBsAg detection was realized on the developed platform. The platform was characterized using cyclic voltammetry (CV) and ECL methods and obtained a linear range of 34.2 pg/mL–34.2 ng/mL with a 34.2 pg/mL (3σ) detection limit. This paper-based ECL sandwich immunoassay showed high sensitivity and selectivity, acceptable reproducibility, fast analysis time and better performance than chemiluminescent immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA) for detecting HBsAg in real clinical serum samples.
Cloth fabrics and smartphones have become the two things people are most familiar with. Especially, smartphones are used as portable personal computers, revolutionizing communication and life types. Here, the screen-printing technology is applied to fabricate carbon electrodes and electrochemical chambers on a single hydrophilic cloth, while the cloth-based electrochemiluminescence (ECL) signals are read out by an inexpensive smartphone. Therefore, the ECL detection is available in both low-cost disposable sensors and portable format, which may be very suitable to be used as non-invasive monitoring tool for medical diagnostics. As the proof-of-principle, lactate oxidase is immobilized onto the working electrode for the lactate measurement. Under optimized conditions, the lactate levels can be quantified over the range of 0.05-2.5 mM, with a detection limit of 0.035 mM and the relative standard deviations of 4.7%, 5.2% and 5.0% for 0.05, 0.5 and 2.5 mM lactate (n = 5). In addition, the proposed biosensor has an acceptable stability and selectivity. Finally, the ECL biosensor is successfully applied for determination of lactate in human saliva. These results show that the presented ECL platform has the potential to be applied to non-invasively detect a variety of analytes of medical interest.
The influence of surfactants and coreactants on Ru(bpy)3²⁺ electrogenerated chemiluminescence (ECL) was investigated comparatively. Specifically, the influence the two tertiary amines, N-butyldiethanolamine (NBEA) and 2-(dibutylamino)ethanol (DBAE) have on the ECL reaction alone and in the presence of the two surfactantes TritonTM X-100 and Zonyl® FSN was investigated, in comparison to the well-studied and established coreactant tripropylamine (TPA). Experiments were conducted on poly(methyl methacrylate) substrates coated with plasma-evaporated gold as used in many miniaturized systems. Upon optimization and study of the various combinations, the combination of NBEA/Zonyl® FSN provided superior ECL signal characteristics. A limit of detection (LOD) of 2.2 nM Ru(bpy)3²⁺ was obtained. Compared to the LOD of 0.59 µM for the commonly used TPA/TritonTM X-100 system, the resulting LOD is enhanced by a factor of 250. In addition, significantly more stable signals lead to an increase of the sensitivity by a factor of 50. This makes the NBEA/Zonyl® FSN system an attractive ECL strategy especially for miniaturized analytical systems. Furthermore, it became clear that previously postulated effects of surfactants on the enhancement of coreactant-based ECL does not translate to other surfactants and coreactants. We could demonstrate that more complicated mechanisms are at play as the ECL intensity for Ru(bpy)3²⁺/NBEA was highest in the presence of Zonyl® FSN, whereas the ECL signal decreased significantly upon introduction of the surfactant with DBAE as coreactant.
Electrochemiluminescence (ECL) systems are of interest from a theoretical point of view and also as the basis for certain types of light-emitting devices. Most iridium complexes that perform well in light-emitting devices also exhibit efficient annihilation ECL. Therefore, as the photophysical and electrochemical properties of iridium complexes began to be investigated for organic light-emitting diode (OLED) applications, they were visited for ECL applications. In general, the exponential growth in reports of iridium complex-based OLEDs had a marked synergistic effect on the field of iridium ECL. The chapter discusses that the energetics of the annihilation reaction compared with excited state energy of the luminophore is an important consideration for efficient co-reactant ECL and one that has only recently received attention. Richter had reported a significant improvement in the co-reactant ECL of [Ru(bpy)3]2+ in the presence of nonionic surfactants at concentrations close to the critical micelle concentration (CMC).
Improving the performance of labeling agents is crucial to the further development of electrochemiluminescence (ECL) related technologies. Although a large number of ECL luminophores beyond ruthenium complexes have been reported so far, there is still a scarcity of studies involving novel ECL labeling agents. Herein, five novel iridium ECL labels and one control label comprising a ruthenium complex have been rationally designed and thoroughly characterized using photophysical techniques, theoretical calculations and electrochemical characterization to assess the ECL properties in this work. Both in coreactant-assisted potential scan experiments and through an annihilation approach, most of these novel iridium labels exhibit equivalent or even-stronger ECL signals than tri-2,2'-bipyridylruthenium(ii) [abbreviated as Ru(bpy)3(2+)] under the same experimental conditions. Most importantly, using the same labeling protocol, bovine serum albumin (BSA) labeled with an iridium label (label 3 in this work) exhibits a much more intense ECL signal (1.9 times) than the same amount labeled with a traditional ruthenium complex (Ru-based Label in this work) in ProCell buffer solution. In addition to the advantage of exhibiting various emission colors, the novel iridium labels reported in this work may offer insight for the further development of ECL-based analytical technology.
In this work, a handheld paper-based bipolar electrode-electrochemiluminescence (P-BPE-ECL) system has been proposed. In this system, a rechargeable battery is used for power supply, while a smartphone is applied for read-out of ECL signal. For the P-BPE-ECL, the carbon ink-based BPE and driving electrodes are screen-printed on the paper, and the wax-screen-printing is employed to fabricate microfluidic channels on electrode-patterned paper. Moreover, the luminol/H2O2-based ECL reaction is applied to demonstrate the quantitative ability of the P-BPE-ECL system. Under optimized conditions, H2O2 can be determined over the range of 5–5000 μM, with a detection limit of 1.75 μM, and relative standard deviations (RSDs) of 7.59%, 3.82% and 4.93% for 10, 100 and 1000 μM H2O2 (n = 5). Thus, this system has an acceptable sensitivity, dynamic range, stability and reproducibility. Finally, the applicability of the P-BPE-ECL system is demonstrated for detection of glucose in phosphate buffer solution (PBS) and artificial urine (AU) samples, with the detection limits of 0.017 mM and 0.030 mM, respectively. Moreover, the P-BPE-ECL system has the ability to perform high-throughput detection of glucose. Therefore, the developed system can provide a new platform for many applications such as point-of-care testing, health diagnosis and environmental monitoring.
A versatile potentiostat based on inexpensive and “off the shelf” components is reported. The platform was shown to be capable of performing simple electrochemistry experiments, suitable for undergraduate level teaching. The simple design and construction enable easy customization to accommodate a broad array of experimental designs. The equipment was used to calculate the diffusion coefficient of potassium ferricyanide in an aqueous solution, and the obtained result was in good agreement with the literature. Although simple in design, the low cost and good performance of the device make it a competitive alternative for teaching laboratories in the fields of both electronics and electrochemistry, and for developing teaching centers that cannot afford a commercial device.
A family of neutral bis-cyclometalated iridium complexes [Ir(C^N)2(LX)] has been investigated as ECL labels under immunoassay conditions. Among them, the complex based on phenylphenanthridine (pphent) as C^N ligand, exhibits outstanding performance and it is a candidate to substitute the commercially available Ru-based label in diagnostics.
Coreactant plays a critical role for the application of electrochemiluminescence (ECL). Herein, N-(3-aminopropyl)diethanolamine (APDEA) has been explored as a potential coreactant for enhancing tris(2,2'-bipyridyl)ruthenium(II) ECL. It is much more effective than tripropylamine at gold and platinum electrodes although it has one primary amine group besides a tertiary amine group. The presence of primary amine group and hydroxyl groups in APDEA promotes the oxidation rates of amine and thus remarkably increases ECL intensity. The ECL intensities of the Ru(bpy)3 (2+)/APDEA system are approximately 10 and 36 times stronger than that of Ru(bpy)3 (2+)/tripropylamine system and about 1.6 and 1.14 times stronger than that of Ru(bpy)3 (2+)/N-butyldiethanolamine system at Au and Pt electrodes, respectively. The ECL intensity of the Ru(bpy)3 (2+)/APDEA system is 2.42 times stronger than that of Ru(bpy)3 (2+)/N-butyldiethanolamine at glassy carbon electrodes.
We examine [Ir(df-ppy)2(pt-TEG)](+) as the first highly water soluble, blue-luminescent iridium(iii) complex for chemiluminescence detection. Marked differences in selectivity were observed between the new complex and the conventional [Ru(bpy)3](2+) reagent, which will enable this mode of detection to be extended to new areas of application.
Several techniques to improve the limit of detection (LOD) of analytical systems for electrochemiluminescent (ECL) reactions are presented. This work focuses on ECL measurement based on photodiodes and techniques to improve it, which were implemented and tested in a portable instrument. Three different topologies of ECL measurement systems were compared. One system consisted of a photomultiplier (PMT) with a photocounting device and a commercial potentiostat. The other two topologies used an ad hoc potentiostat and a photodiode with different conditioning electronics: one with Field Programmable Analog Arrays (FPAA) and the other using conventional analog electronics with a programmable gain amplifier (PGA). The three systems were tested using triethylamine (TEA) as the analyte and tris(2,2′bipyridyl)ruthenium(II) as the transduction chemistry. The detection limit achieved with the system with conventional electronics and PGA was 0.02 mg l-1, nine times lower than the system with FPAA and 45 times lower than the commercial system with the photomultiplier (PMT).
A low-cost system to generate, control and detect electrochemiluminescence using a mobile smartphone is described. A simple tone-detection integrated circuit is used to switch power sourced from the phone's Universal Serial Bus (USB) ‘On-The-Go’ (OTG) port, using audible tone pulses played over the device's audio jack. We have successfully applied this approach to smartphones from different manufacturers and with different operating system versions. ECL calibrations of a common luminophore, tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)3]2+), with 2-(dibutylamino)ethanol (DBAE) as a co-reactant, showed no significant difference in light intensities when an electrochemical cell was controlled by a mobile phone in this manner, compared to the same calibration generated using a conventional potentiostat. Combining this novel approach to control the applied potential with the measurement of the emitted light through the smart phone camera (using an in-house built Android app), we explored the ECL properties of a water-soluble iridium(III) complex that emits in the blue region of the spectrum. The iridium(III) complex exhibited superior co-reactant ECL intensities and limits of detection to that of the conventional [Ru(bpy)3]2+ luminophore.
The great success of electrochemiluminescence (ECL) for in vitro diagnosis (IVD) and its promising potential in light-emitting devices greatly promote recent ECL studies. More than 45% of ECL articles were published after 2010, and the first international meeting on ECL was held in Italy in 2014. This critical review discusses recent vibrant developments in ECL, and highlights novel ECL phenomena, such as wireless ECL devices, bipolar electrode-based ECL, light-emitting electrochemical swimmers, upconversion ECL, ECL resonance energy transfer, thermoresponsive ECL, ECL using shape-controlled nanocrystals, and ECL as an ion-selective electrode photonic reporter, a paper-based microchip, and a self-powered microfluidic ECL platform. We also comment on the latest progress in bioassays, light-emitting devices and, the computational approach for the ECL mechanism study. Finally, perspectives and key challenges in the near future are addressed (198 references).
The concept and realization of microfluidic total analysis systems (microTAS) have revolutionized the analytical process by integrating the whole breadth of analytical techniques into miniaturized systems. Paramount for efficient and competitive microTAS are integrated detection strategies, which lead to low limits of detection while reducing the sample volume. The concept of electrochemiluminescence (ECL) has been intriguing ever since its introduction based on Ru(bpy)3 (2+) by Tokel and Bard [1] (J Am Chem Soc 1853:2862-2863, 1972), especially because of its immense sensitivity, nonexistent auto-luminescent background signal, and simplicity in experimental design. Therefore, integrating ECL detection into microTAS is a logical consequence to achieve simple, yet highly sensitive, sensors. However, published microanalytical devices employing ECL detection focus in general on traditional ECL chemistry and have yet to take advantage of advances made in standard bench-top ECL strategies. This review will therefore focus on the most recent advancements in microfluidic ECL approaches, but also evaluate the potential impact of bench-top ECL research progress that would further improve performance and lower limits of detection of micro analytical ECL systems, ensuring their desirability as detection principle for microTAS applications.
In this study, a novel solid-state Ru(bpy)3(2+) electrochemiluminescence (ECL) sandwiched immunosensor for sensitive detection of α-fetoprotein (AFP) was constructed based on poly(ethylenimine) (PEI) functionalized reduced graphene oxide (PEI-rGO) and Au nanoparticles (AuNPs) decorated polyamidoamine (PAMAM) dendrimers. Both PEI and PAMAM are polymers with a lot of amino groups, which are able to serve as good co-reactant to remarkably enhance the ECL signal of Ru(bpy)3(2+). For improving the poor conductivity of PAMAM, the AuNPs were decorated on the amino groups of PAMAM. Through Au-N bonds, the formed AuNPs-PAMAM was decorated on the PEI-rGO. The obtained AuNPs-PAMAM/PEI-rGO was introduced to immobilize the detection antibody (Ab2). Then, the Ab2 labeled AuNPs-PAMAM/PEI-rGO was modified onto the glass carbon electrode surface via sandwiched immunoreactions. The ECL substrate was prepared by mixing nafion and the complex (Ru-PtNPs) of Pt nanoparticles (PtNPs) and Ru(bpy)3(2+), which could reduce the consumption of Ru complex, simplify the operation and enhance the ECL efficiency. The experimental results demonstrated that the proposed immunosensor had good response to AFP. The linear range was from 0.01pgmL(-1) to 10ngmL(-1) with a low detection limit of 3.3fgmL(-1). Meanwhile, with satisfying stability, selectivity and reproducibility, the proposed sandwiched immunosensor was presented to possess good potential in clinical detection.
This review presents a general picture of the current trends and developments (2008-2013) related to electrochemiluminescence-based immunosensors. It briefly covers the milestones of qualitative changes in the field of electrochemiluminescent immunosensors; the peculiarities of the electrochemiluminescent immunoassay formats; the basic mechanisms of ECL detection, main features of early and ongoing approaches in electrochemiluminescent immunoassay commercial instruments, and the recent developments in fabrication of solid-state electrochemiluminescent immunosensors. Moreover, systematized data on biomarkers, immunoassay formats, and novel types of electrochemiluminescent label and immobilization support, such as semiconductor nanocrystals, porous noble metals, graphene, TiO2 nanotube arrays, metal-organic composites, multiwall carbon nanotubes, liposomes, photolummonescent carbone nanocrystals are presented as a table. Considerable efforts have also been devoted towards the following two key points: multiplexing analysis (multi-label, and the multianalyte strategies) and integration in microfluidic lab-on-paper devices with capabilities for point-to-care diagnostics. An immuno-like electrochemiluminescent sensor (based on synthetic receptors-molecularly imprinted polymers), as a new alternative to traditional electrochemiluminescent immunoassay is highlighted. Future perspectives and possible challenges in this rapidly developing area are also discussed.