[show abstract][hide abstract] ABSTRACT: B lymphocyte induced maturation protein 1 (Blimp1) is a transcription factor that is critical for differentiation and antibody production in plasma cells. In order to understand the mechanism of systemic lupus erythematosus (SLE), the role of Blimp1 expression was studied in patients with SLE and in healthy control subjects. And Blimp1 tissue distribution in MRL/lpr lupus mice was also investigated.
The mRNA expression level of Blimp1 was analyzed by fluorescent real time PCR and compared between the 40 SLE patients and 30 control subjects. Expression of CD138, CD27 and CD19 in peripheral blood cells was analyzed by flow cytometry. Blimp1 mRNA and protein expression levels and tissue distribution in the kidneys, spleen and lymph nodes of MRL/lpr lupus and normal mice were analyzed.
Blimp1 mRNA expression level was 2.1 times greater in the SLE group as compared to the control group. The increased mRNA expression of Blimp1 seemed to be related to SLE disease activity and anti-nuclear antibody (ANA) titer. In SLE patients, the CD138+ plasma cells increased as the CD27+ cells decreased. Compared with normal mice, Blimp1 was strongly expressed in the kidneys, lymph nodes and spleen of MRL/lpr lupus mice. The expression level of Blimp1 mRNA in the kidneys, lymph nodes and spleen of MRL/lpr lupus mice was much higher than normal mice (1.76, 2.02, and 2.05 times greater, respectively, P<0.05). Similarly, protein levels in the above mentioned organs were also much higher (1.54, 1.99, and 2.21 times greater, respectively, P<0.05).
The elevated expression of Blimp1 in SLE patients and in the lupus mouse model is correlated with increases in plasma cells, autoantibodies and disease activity. It is closely related to differentiation of B-lymphocytes, antibody production and renal lesions. Blimp1 may play a role in SLE disease development.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to evaluate the potential value of circulating miRNA-122a and miRNA-221 in the diagnosis of hepatocellular carcinoma.
Serum samples were obtained from 85 patients with hepatocellular carcinoma and 85 age-matched and sex-matched healthy volunteers. miRNAs were isolated from the serum samples, and alfa-fetoprotein levels were determined. Expression of miRNA-122a and miRNA-221 in cases and controls was quantified using U6 sn RNA as the internal control. The diagnostic value of miRNA-122a, miRNA-221, and alfa-fetoprotein was compared by receiver operating characteristic analysis.
The serum miRNA-122a level in patients with hepatocellular carcinoma was significantly reduced in comparison with healthy controls and correlated with known risk factors for hepatocellular carcinoma. Circulating miRNA-221 in patients with hepatocellular carcinoma was higher compared with the control group, but the difference was not statistically significant. Receiver operating characteristic analysis revealed that the diagnostic power of miRNA-122a was suboptimal compared with serum alfa-fetoprotein. Further, the serum alfa-fetoprotein and miRNA-122a combined classifier resulted in performance similar to that of alfa-fetoprotein alone.
The serum miRNA-122a level correlates with risk factors for hepatocellular carcinoma. However, use of miRNA-122a as a diagnostic tool for hepatocellular carcinoma is not superior to alfa-fetoprotein. Further analysis is needed to evaluate the diagnostic power of plasma miRNA-122a for hepatocellular carcinoma.
OncoTargets and Therapy 01/2013; 6:577-83. · 2.07 Impact Factor
[show abstract][hide abstract] ABSTRACT: Risk for Ovarian Malignancy Algorithm (ROMA) and Human epididymis protein 4 (HE4) appear to be promising predictors for epithelial ovarian cancer (EOC), however, conflicting results exist in the diagnostic performance comparison among ROMA, HE4 and CA125.
Remote databases (MEDLINE/PUBMED, EMBASE, Web of Science, Google Scholar, the Cochrane Library and ClinicalTrials.gov) and full texts bibliography were searched for relevant abstracts. All studies included were closely assessed with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2). EOC predictive value of ROMA was systematically evaluated, and comparison among the predictive performances of ROMA, HE4 and CA125 were conducted within the same population. Sensitivity, specificity, DOR (diagnostic odds ratio), LR ± (positive and negative likelihood ratio) and AUC (area under receiver operating characteristic-curve) were summarized with a bivariate model. Subgroup analysis and sensitivity analysis were used to explore the heterogeneity.
Data of 7792 tests were retrieved from 11 studies. The overall estimates of ROMA for EOC predicting were: sensitivity (0.89, 95% CI 0.84-0.93), specificity (0.83, 95% CI 0.77-0.88), and AUC (0.93, 95% CI 0.90-0.95). Comparison of EOC predictive value between HE4 and CA125 found, specificity: HE4 (0.93, 95% CI 0.87-0.96) > CA125 (0.84, 95% CI 0.76-0.90); AUC: CA125 (0.88, 95% CI 0.85-0.91) > HE4 (0.82, 95% CI 0.78-0.85). Comparison of OC predictive value between HE4 and CA125 found, AUC: CA125 (0.89, 95% CI 0.85-0.91) > HE4 (0.79, 95% CI 0.76-0.83). Comparison among the three tests for EOC prediction found, sensitivity: ROMA (0.86, 95%CI 0.81-0.91) > HE4 (0.80, 95% CI 0.73-0.85); specificity: HE4 (0.94, 95% CI 0.90-0.96) > ROMA (0.84, 95% CI 0.79-0.88) > CA125 (0.78, 95%CI 0.73-0.83).
ROMA is helpful for distinguishing epithelial ovarian cancer from benign pelvic mass. HE4 is not better than CA125 either for EOC or OC prediction. ROMA is promising predictors of epithelial ovarian cancer to replace CA125, but its utilization requires further exploration.
[show abstract][hide abstract] ABSTRACT: Urinary trypsinogen-2 has been implicated as a promising biomarker for the early diagnosis of acute pancreatitis (AP). The meta-analysis was used to establish the overall accuracy of urinary trypsinogen-2 test for diagnosing AP.
Based on comprehensive searches of the PubMed and Embase databases, we identified and abstracted outcome data from all articles evaluating the diagnostic value of urinary trypsinogen-2. A summary estimate for sensitivity, specificity, 95% confidence region and 95% prediction region was calculated using the bivariate random-effects approach.
The meta-analysis included 13 studies (2342 patients, the proportion of severe AP from 13.21% to 30.00%). Overall, the pooled sensitivity was 82.3% (95%CI 79.3%-85.1%) and specificity was 93.5% (95%CI 92.2%-94.6%). The diagnostic odds ratios (DOR) was 85.23 (95%CI 40.14-180.99). The area under the summary ROC curve (AUC) was 0.9673.
The urinary trypsinogen-2 test is a reliable and rapid method for the early diagnosis of AP.
[show abstract][hide abstract] ABSTRACT: The accurate and high-throughput detection of drug resistance-related multiple point mutations remains a challenge. Although the combination of molecular beacons with bio-immobilization technology, such as microarray, is promising, its application is difficult due to the ineffective immobilization of molecular beacons on the chip surface. Here, we propose a novel asymmetric-loop molecular beacon in which the loop consists of 2 parts. One is complementary to a target, while the other is complementary to an oligonucleotide probe immobilized on the chip surface. With this novel probe, a two-phase hybridization assay can be used for simultaneously detecting multiple point mutations. This assay will have advantages, such as easy probe availability, multiplex detection, low background, and high-efficiency hybridization, and may provide a new avenue for the immobilization of molecular beacons and high-throughput detection of point mutations.
Medical science monitor: international medical journal of experimental and clinical research 04/2012; 18(4):HY5-8. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: This manuscript describes a new technique for detecting single-nucleotide polymorphisms (SNPs) by integrating a leaky surface acoustic wave (LSAW) biosensor, enzymatic DNA ligation and enzymatic signal amplification. In this technique, the DNA target is hybridized with a capture probe immobilized on the surface of a LSAW biosensor. Then, the hybridized sequence is ligated to biotinylated allele-specific detection probe using Taq DNA ligase. The ligation does not take place if there is a single-nucleotide mismatch between the target and the capture probe. The ligated detection probe is transformed into a streptavidin-horseradish peroxidase (SA-HRP) terminal group via a biotin-streptavidin complex. Then, the SA-HRP group catalyzes the polymerization of 3,3-diaminobenzidine (DAB) to form a surface precipitate, thus effectively increasing the sensitivity of detecting surface mass changes and allowing detection of SNPs. Optimal detection conditions were found to be: 0.3 mol/L sodium ion concentration in PBS, pH 7.6, capture probe concentration 0.5 μmol/L and target sequence concentration 1.0 μmol/L. The detection limit was found to be 1 × 10(-12)mol/L. Using this technique, we were able to detect a single-point mutation at nucleotide A2293G in Japanese encephalitis virus.
[show abstract][hide abstract] ABSTRACT: Xpert MTB/RIF (Cepheid) assay has been introduced for the diagnosis of tuberculosis (TB) and RIF-resistance. The meta-analysis was used to establish the overall accuracy of Xpert MTB/RIF assay for diagnosing TB and RIF-resistance.
Based on comprehensive searches of the Pubmed and Embase, we identified outcome data from all articles estimating diagnostic accuracy with Xpert MTB/RIF assay. A summary estimation for sensitivity, specificity, diagnostic odds ratios (DOR) and the area under the summary ROC curve (AUC) was calculated by using the bivariate random-effects approach.
The meta-analysis included 18 studies (10,224 suspected specimens). The summary estimate was 90.4% (95%CI 89.2%-91.4%) for sensitivity, 98.4% (95%CI 98.0%-98.7%) for specificity and 328.3/0.9822 for DOR/AUC in pulmonary tuberculosis (PTB). The sensitivity, specificity and DOR/AUC of detecting RIF-resistance were 94.1%, 97.0% and 177.8/0.9832, respectively. For extrapulmonary tuberculosis, the overall pooled sensitivity was 80.4% and specificity was 86.1%. The findings in subgroup analysis were as follows: the accuracy of Xpert MTB/RIF assay is higher in smear-positive specimens and the sensitivity of diagnosing PTB in adults was higher than that in children (90.8% versus 74.3%).
TB and RIF-resistance can be rapidly and effectively diagnosed with Xpert MTB/RIF assay.
The Journal of infection 02/2012; 64(6):580-8. · 4.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: The association between CD209 promoter polymorphisms (-336A/G, -871A/G) and tuberculosis (TB) risk has been widely reported, but results of previous studies remain controversial and ambiguous. To assess the association between CD209 polymorphisms and TB risk, a meta-analysis was performed.
Based on comprehensive searches of the PubMed, Embase, Web of Science, Weipu, and CBM databases, we identified outcome data from all articles estimating the association between CD209 polymorphisms and TB risk. The pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated.
A total of 14 studies with 3,610 cases and 3,539 controls were identified. There was no significant association between CD209 -336A/G polymorphism and TB risk (OR = 1.04, 95% CI = 0.91-1.19 for G vs. A; OR = 1.13, 95% CI = 0.84-1.53 for GG vs. AA; OR = 1.04, 95% CI = 0.87-1.24 for GG+AG vs. AA; OR = 1.11, 95% CI = 0.88-1.39 for GG vs. AG+AA). However, the significant association was revealed for Asians in GG vs. AA (OR = 2.48, 95% CI = 1.46-4.22, P = 0.0008) and GG vs. AG+AA (OR = 2.10, 95% CI = 1.33-3.32, P = 0.001). For the CD209 -871A/G polymorphism, lack of an association was also found (OR = 0.81, 95% CI = 0.70-0.95 for G vs. A; OR = 1.00, 95% CI = 0.52-1.93 for GG vs. AA; OR = 0.73, 95% CI = 0.60-0.89 for GG+AG vs. AA; OR = 1.09, 95% CI = 0.57-2.10 for GG vs. AG+AA).
The present meta-analysis suggested that CD209 promoter polymorphisms (-336A/G, -871A/G) were unlikely to substantially contribute to TB susceptibility. However, the GG genotype of CD209 -336A/G polymorphism might be a genetic risk factor that increases TB susceptibility for Asians in GG vs. AA and GG vs. AG+AA.
PLoS ONE 01/2012; 7(7):e41519. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: High-sensitivity C-reactive protein (hs-CRP) assay is of great clinical importance in predicting risks associated with coronary heart disease. Existing hs-CRP assays either require complex operation or have low throughput and cannot be routinely implemented in rural settings due to limited laboratory resources.
We developed a novel hs-CRP assay capable of simultaneously quantifying over 90 clinical samples by using quantum dots-labeled immunoassay within a standard 96-well microplate. The specificity of the assay was enhanced by adopting two monoclonal antibodies (mAbs) that target distinct hs-CRP epitopes, serving as the coating antibody and the detection antibody, respectively. In the presence of hs-CRP antigen, the fluorescence intensity of the mAb-Ag-mAb sandwich complex captured on the microplate can be read out using a microplate reader.
The proposed hs-CRP assay provides a wide analytical range of 0.001-100 mg/L with a detection limit of 0.06 (0.19) μg/L within 1.5 h. The accuracy of the proposed assay has been confirmed for low coefficient of variations (CVs), 2.27% (intra-assay) and 8.52% (inter-assay), together with recoveries of 96.7-104.2%. Bland-Altman plots of 104 clinical samples exhibited good consistency among the proposed assay, commercial high-sensitivity ELISA, and nephelometry, indicating the prospects of the newly developed hs-CRP assay as an alternative to existing hs-CRP assays.
The developed assay meets the needs of the rapid, sensitive and high-throughput determination of hs-CRP levels within a short time using minimal resources. In addition, the developed assay can also be used to detect and quantify other diagnostic biomarkers by immobilizing specific monoclonal antibodies.
Journal of Translational Medicine 01/2012; 10:24. · 3.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Researchers have demonstrated dead cells in radiofrequency ablation (RFA) lesions that have morphological similarities to viable tumor cells and are thus referred to as ghost cells. However, studies on how long ghost cells persist have not been systematically performed.
A tumor model was established by implanting VX2 tumor tissue into the livers of 48 New Zealand rabbits. Two weeks later, these tumors were eliminated with RFA. The lesions were resected at 0 weeks, 1 week, 2 weeks, 4 weeks, 8 weeks, or 12 weeks after treatment, and samples were stained either with hematoxylin and eosin (HE) or nicotinamide adenine dinucleotide (NADH). The presence of the cells and the morphological changes that they underwent were examined by light microscopy.
Four weeks after RFA, there were no obvious morphological changes observed in HE-stained ghost cells, and NADH staining revealed no viable cells. Eight weeks after RFA, the cell structure became indistinct. Twelve weeks after RFA, ghost cells were no longer present.
The morphological characteristics of ghost cells are maintained for at least 4 weeks, during which time HE staining cannot be used to differentiate ghost cells from residual tumor cells. NADH staining for cell viability is necessary to differentiate residual tumor cells from ghost cells. This evidence adds to our understanding of the mechanisms of RFA when used on solid tumors.
PLoS ONE 01/2012; 7(12):e53158. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Early detection of mixed aerobic-anaerobic infection has been a challenge in clinical practice due to the phenotypic changes in complex environments. Surface plasmon resonance (SPR) biosensor is widely used to detect DNA-DNA interaction and offers a sensitive and label-free approach in DNA research.
In this study, we developed a single-stranded DNA (ssDNA) amplification technique and modified the traditional SPR detection system for rapid and simultaneous detection of mixed infections of four pathogenic microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, Clostridium tetani and Clostridium perfringens).
We constructed the circulation detection well to increase the sensitivity and the tandem probe arrays to reduce the non-specific hybridization. The use of 16S rDNA universal primers ensured the amplification of four target nucleic acid sequences simultaneously, and further electrophoresis and sequencing confirmed the high efficiency of this amplification method. No significant signals were detected during the single-base mismatch or non-specific probe hybridization (P < 0.05). The calibration curves of amplification products of four bacteria had good linearity from 0.1 nM to 100 nM, with all R(2) values of >0.99. The lowest detection limits were 0.03 nM for P. aeruginosa, 0.02 nM for S. aureus, 0.01 nM for C. tetani and 0.02 nM for C. perfringens. The SPR biosensor had the same detection rate as the traditional culture method (P < 0.05). In addition, the quantification of PCR products can be completed within 15 min, and excellent regeneration greatly reduces the cost for detection.
Our method can rapidly and accurately identify the mixed aerobic-anaerobic infection, providing a reliable alternative to bacterial culture for rapid bacteria detection.
Journal of Translational Medicine 01/2011; 9:85. · 3.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: The heat-sink effect produced by rapid blood flow through large vessels (diameter (D) ≥ 5 mm) is an important factor that influences ablation zone size after radiofrequency ablation (RFA). Currently, however, the interactions between hepatic RFA lesions and large vessels are not well understood. The purpose of this study was to examine the effects of RFA lesions occurring near large vessels (D ≥ 5 mm) in the canine liver.
Thirty healthy adult mongrel dogs were used, with 15 dogs randomly assigned to groups I and II. In group I, the closest distance from the tip of the RFA electrode to the large vessel (D ≥ 5 mm) was more than 20 mm; in group II, this distance to the wall of the inferior vena cava (IVC) was no more than 5 mm. RFA was performed on the liver of each dog according to standard procedures. The blood flow velocity of the IVC, the computerised tomography (CT), the pathological characteristics of the RFA lesions and procedure-related complications were examined.
No death or complications occurred in any dogs. Vascular walls were not affected, except for when the tips of the electrode stuck to the IVC. The coagulative necrosis region was decreased, and its shape was fusiform close to the IVC. Some normal hepatic cells were found in the necrotic region near the IVC.
It is both safe and feasible to perform RFA near the IVC. The shape and size of the coagulation zone should be considered when electrodes are placed in this area. Near the IVC, the size of the coagulation zone was decreased, and it was incompletely formed.
International Journal of Hyperthermia 01/2011; 27(2):116-23. · 2.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: We developed a 2×5 model quartz crystal microbalance (QCM) DNA biosensor array for detection of five bacteria, which based on hybridization analysis of bacterial 16S–23S rDNA internal transcribed spacer (ITS) region. A pair of universal primers was designed for PCR amplification of the ITSs. The PCR products were analyzed by the biosensor. We used gold nanoparticles to amplify the frequency shift signals. Fifty clinical samples were detected by both the biosensor and conventional bacteria culture method. We found a linear quantitative relationship between frequency shift and logarithmic concentration of synthesized oligonucleotides or bacteria cells. The measurable concentration ranged from 10−12 to 10−8M for synthesized oligonucleotides and 1.5×102 to 1.5×108CFU/mL for bacteria. The 10−12M of synthesized oligonucleotides or 1.5×102CFU/mL of Pseudomonas aeruginosa could be detected by the biosensor system. The detection could be completed within 5h including the PCR amplification procedure. Compared with bacteria culture method, the detection sensitivity and specificity of the biosensor system were 94.12% and 90.91%, respectively. There was no significant difference between these two methods (P=0.625>0.05). The biosensor system provides a rapid and sensitive method for parallelized and quantitative analysis of multiple pathogenic bacteria in clinical diagnosis.
Sensors and Actuators B-chemical - SENSOR ACTUATOR B-CHEM. 01/2011; 155(2):500-504.
[show abstract][hide abstract] ABSTRACT: A method for the simultaneous and economical determination of many trace elements in human milk is developed. Two multi-element hollow cathode lamps (HCLs) were used instead of single-element HCLs to improve the sample throughput of flame atomic absorption spectroscopy (FAAS). The microwave digestion of milk is optimized prior to detection, and the performance characteristics of the improved analysis method are identified. Clinical samples are detected by both FAAS and inductively coupled plasma-optical emission spectroscopy (ICP-OES) for methodology evaluation. Results reveal that the proposed FAAS with multi-element HCLs could determine six essential minerals and trace elements within 15 min. This method provides a linear analytical range of 0.01-10 mg L(-1). For Ca, Cu, Fe, Mg, Mn, and Zn, the limits of determination are 1.5, 3, 1.8, 2.2, 2.1, and 1.3 microg L(-1), respectively. The mean relative standard deviations (RSDs) of intra- and interassays are lower than 7%. Excellent operational characteristics of rapidity, simplicity, and economy make the proposed method a promising one for the quantification of trace elements in human milk in clinics of underdeveloped areas.
Journal of Agricultural and Food Chemistry 09/2010; 58(17):9396-400. · 2.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: Fibrinogen can transform fibrin through an agglutination reaction, finally forming fibrin polymer with grid structure. The density and viscosity of the reaction system changes drastically during the course of agglutination. In this research, we apply an independently-developed piezoelectric agglutination sensor to detect the fibrinogen agglutination reaction in patients with coronary heart diseases. The terminal judgment method of determining plasma agglutination reaction through piezoelectric agglutination sensor was established. In addition, the standard curve between plasma agglutination time and fibrinogen concentration was established to determinate fibrinogen content quantitatively. The results indicate the close correlation between the STAGO paramagnetic particle method and the method of piezoelectric agglutination sensor for the detection of Fibrinogen. The correlation coefficient was 0.91 (γ = 0.91). The determination can be completed within 10 minutes. The fibrinogen concentration in the coronary heart disease group was significantly higher than that of the healthy control group (P < 0.05). The results reveal that high fibrinogen concentration is closely correlated to the incurrence, development and prognosis of coronary heart diseases. Compared with other traditional methods, the method of piezoelectric agglutination sensor has some merits such as operation convenience, small size, low cost, quick detecting, good precision and the common reacting agents with paramagnetic particle method.
[show abstract][hide abstract] ABSTRACT: A novel multi-channel 2 x 5 model of piezoelectric (PZ) micro-array immunosensor has been developed for quantitative detection of human immunoglobulinE (IgE) in serum. Every crystal unit of the fabricated piezoelectric IgE micro-array immunosensor can oscillate without interfering each other. A multi-channel 2 x 5 model micro-array immunosensor as compared with the traditional one-channel immunosensor can provide eight times higher detection speeds for IgE assay. The anti-IgE antibody is deposited on the gold electrode's surface of 10 MHz AT-cut quartz crystals by SPA (staphylococcal protein A), and serves as an antibody recognizing layer. The highly ordered antibody monolayers ensure well-controlled surface structure and offer many advantages to the performance of the sensor. The uniform amount of antibody monolayer coated by the SPA is good, and non-specific reaction caused by other immunoglobulin in sample is found. The fabricated PZ immunosensor can be used for human IgE determination in the range of 5-300 IU/ml with high precision (CV is 4%). 50 human serum samples were detected by the micro-array immunosensor, and the results agreed well with those given by the commercially ELISA test kits. The correlation coefficient is 0.94 between ELISA and PZ immunosensor. After regeneration with NaOH the coated immunosensor can be reused 6 times without appreciable loss of activity.
Journal of Nanoscience and Nanotechnology 01/2007; 6(12):3828-34. · 1.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: Urinary proteins are predictive and prognostic markers for diabetes nephropathy. Conventional methods for the quantification of urinary proteins, however, are time-consuming, and most require radioactive labeling. We designed a label-free piezoelectric quartz crystal microbalance (QCM) immunosensor array to simultaneously quantify 4 urinary proteins.
We constructed a 2 x 5 model piezoelectric immunosensor array fabricated with disposable quartz crystals for quantification of microalbumin, alpha1-microglobulin, beta2-microglobulin, and IgG in urine. We made calibration curves after immobilization of antibodies at an optimal concentration and then evaluated the performance characteristics of the immunosensor with a series of tests. In addition, we measured 124 urine samples with both QCM immunosensor array and immunonephelometry to assess the correlation between the 2 methods.
With the QCM immunosensor array, we were able to quantify 4 urinary proteins within 15 min. This method had an analytical interval of 0.01-60 mg/L. The intraassay and interassay imprecisions (CVs) were <10%, and the relative recovery rates were 90.3%-109.1%. Nonspecificity of the immunosensor was insignificant (frequency shifts <20 Hz). ROC analyses indicated sensitivities were > or =95.8% and, specificities were > or =76.3%. Bland-Altman difference plots showed the immunosensor array to be highly comparable to immunonephelometry.
The QCM system we designed has the advantages of being rapid, label free, and highly sensitive and thus can be a useful supplement to commercial assay methods in clinical chemistry.