scholarly journals Single-step label-free nanowell immunoassay accurately quantifies serum stress hormones within minutes

2021 ◽  
Vol 7 (27) ◽  
pp. eabf4401
Author(s):  
S. Reza Mahmoodi ◽  
Pengfei Xie ◽  
Daniel P. Zachs ◽  
Erik J. Peterson ◽  
Rachel S. Graham ◽  
...  
Keyword(s):  
Human Serum ◽  
Real Time ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Label Free ◽  
Serum Samples ◽  
Electrode Gap ◽  
Buffer Solution ◽  
Human Serum Samples ◽  
Free Cortisol

A non-faradaic label-free cortisol sensing platform is presented using a nanowell array design, in which the two probe electrodes are integrated within the nanowell structure. Rapid and low volume (≤5 μl) sensing was realized through functionalizing nanoscale volume wells with antibodies and monitoring the real-time binding events. A 28-well plate biochip was built on a glass substrate by sequential deposition, patterning, and etching steps to create a stack nanowell array sensor with an electrode gap of 40 nm. Sensor response for cortisol concentrations between 1 and 15 μg/dl in buffer solution was recorded, and a limit of detection of 0.5 μg/dl was achieved. Last, 65 human serum samples were collected to compare the response from human serum samples with results from the standard enzyme-linked immunosorbent assay (ELISA). These results confirm that nanowell array sensors could be a promising platform for point-of-care testing, where real-time, laboratory-quality diagnostic results are essential.

scholarly journals Seroprevalence of Jamestown Canyon virus in the Japanese general population

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Hirofumi Kato ◽  
Masaaki Satoh ◽  
Madoka Kawahara ◽  
Satoshi Kitaura ◽  
Tomoki Yoshikawa ◽  
...  
Keyword(s):  
General Population ◽  
Human Serum ◽  
Health Agency ◽  
Febrile Illness ◽  
Central Nervous System Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Assay ◽  
Serum Samples ◽  
Human Serum Samples ◽  
Jamestown Canyon Virus

Abstract Background Jamestown Canyon virus (JCV) is a mosquito-borne orthobunyavirus that causes acute febrile illness, meningitis, and meningoencephalitis, mainly among adults. JCV is widely distributed in North America and the number of JCV cases in the U.S. has increased in recent years. Therefore, the central nervous system disease caused by JCV can be considered a potentially re-emerging viral disease. However, the seroprevalence of JCV is unknown in Japan. The purpose of this study is to evaluate the seroprevalence of JCV in the Japanese population. Methods We used an IgG enzyme-linked immunosorbent assay (IgG-ELISA) with JCV-infected cell-lysates and/or a neutralizing (NT) antibody assay. The cut-off value of IgG-ELISA was determined using IgG-ELISA to analyze serum specimens from 37 healthy Japanese donors. IgG-ELISA was validated by assessing its sensitivity and specificity, using 38 human serum samples previously tested for the presence or absence of antibodies against JCV and snowshoe hare virus (SSHV), in an in-house NT antibody assay conducted by the Public Health Agency of Canada. The seroepidemiological study was performed using IgG-ELISA and NT antibody assay to analyze 246 human serum samples from the serum bank of the National Institute of Infectious Diseases (NIID) in Japan. Results The cut-off value of IgG-ELISA was determined at 0.20, based on the mean (− 0.075) and standard deviation (0.092) values using Japanese donors’ sera. The sensitivity and the specificity of IgG-ELISA determined using 25 JCV-positive and 4 JCV-negative serum samples were 96 and 100%, respectively. Analysis of the 246 Japanese serum samples revealed that no specimen showed a higher value than the cut-off value of IgG-ELISA, and no sample tested positive by the NT antibody assay. Conclusions Our results showed that JCV is not circulating significantly in Japan. To the best of our knowledge, this is the first report to demonstrate the seroprevalence of JCV in the general population in Japan.

scholarly journals Antibody Responses to Escherichia coli O157 and Other Lipopolysaccharides in Healthy Children and Adults

2003 ◽  
Vol 10 (5) ◽  
pp. 797-801 ◽  
Author(s):  
Armando Navarro ◽  
Carlos Eslava ◽  
Ulises Hernandez ◽  
Jose Luis Navarro-Henze ◽  
Magali Aviles ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Serum ◽  
Western Blotting ◽  
Rabbit Serum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Children ◽  
Serum Samples ◽  
E Coli ◽  
Human Serum Samples ◽  
Bactericidal Activities

ABSTRACT In Mexico, diarrheal disease due to different serotypes of Escherichia coli is highly prevalent, with only sporadic isolation of O157 non-H7 strains. This could be due to exposure to the O157 or related E. coli lipopolysaccharide (LPS), such as O7 or O116, at an early age. By using enzyme-linked immunosorbent assay (ELISA) and Western blotting, the present study analyzed 605 serum samples from Mexican adults and infants without clinical symptoms of disease for the presence of antibodies to these three E. coli LPSs. The bactericidal activities of homologous and heterologous rabbit and human serum samples against O7, O116, and O157 E. coli LPSs were also determined. By using a cutoff point of 0.7, it was found by the ELISAs that 28 of 562 (5%) of the serum samples from adolescents and adults and 2 of 43 (5%) of the serum samples from infants less than 1 year of age reacted with the O157 LPS. By using cutoff points between 0.4 and 0.699, the proportion of serum samples from both age groups that reacted with the O157 LPS increased to 20%. Western blotting analysis of selected serum samples that showed an intermediate response against the O157 LPS by the ELISAs showed that 61 of 88 (69%) reacted with the same LPS. A similar result was observed for maternal milk samples. The bactericidal activities of rabbit serum samples against the O7, O116, and O157 LPSs showed that they were positive for both homologous and heterologous antigens. Similar results were observed with the human serum samples. O157 non-H7 strains were identified in only 10% of the E. coli strains isolated from 263 Mexican children with and without diarrhea over the past 15 years. This absence of O157:H7 strains in Mexico may be associated with the presence of antibodies against O157 or related E. coli LPSs.

scholarly journals Gold-Labeled Nanoparticle-Based Immunoresonance Scattering Spectral Assay for Trace Apolipoprotein AI and Apolipoprotein B

2006 ◽  
Vol 52 (7) ◽  
pp. 1389-1394 ◽  
Author(s):  
Zhiliang Jiang ◽  
Shuangjiao Sun ◽  
Aihui Liang ◽  
Wenxin Huang ◽  
Aimiao Qin
Keyword(s):  
Gold Nanoparticles ◽  
Human Serum ◽  
Linear Regression Analysis ◽  
Trisodium Citrate ◽  
Risk Indicators ◽  
Apolipoprotein Ai ◽  
Serum Samples ◽  
Buffer Solution ◽  
Solution Ph ◽  
Human Serum Samples

Abstract Background: Apolipoprotein AI (ApoAI) and ApoB are risk indicators of cardiovascular disease. We describe the use of immunoresonance scattering to measure the ApoAI and ApoB in serum. Methods: We used a trisodium citrate method to prepare 9.0-nm gold nanoparticles labeled with goat anti-human ApoAI and ApoB antibodies. The immune reaction between gold-labeled antibodies and antigens took place in Na2HPO4-NaH2PO4 buffer solution (pH 6.4 for ApoAI and pH 6.0 for ApoB) in the presence of 75 g/L polyethylene glycol (PEG). We used a transmission electron microscope to observe the shape of the gold nanoparticles. Results were compared with those obtained by immunoturbidimetric methods. Twenty-five human serum samples were assayed by the immunoresonance scattering assay preset with the data indicated and by an immunoturbidimetric assay. Results: The presence of PEG greatly enhanced the intensity of resonance-scattering peaks at 560 nm. The intensity (ΔI) was proportional to concentration at 0.00833–0.3333 mg/L ApoAI and 0.00197–0.1972 mg/L ApoB. The detection limits were 2.04 and 0.96 μg/L for ApoAI and ApoB, respectively. The results for human serum samples were in agreement with those obtained with an immunoturbidimetric method. Linear regression analysis revealed a correlation coefficient, slope, and intercept of 0.915, 0.966, and 68.53 mg/L, respectively, for ApoAI and 0.919, 0.996, and 15.46 mg/L for ApoB. Conclusion: This method showed high sensitivity and good selectivity for quantitative determination of ApoAI and ApoB in human serum, with satisfactory results.

Detection of Colorado Tick Fever viral RNA in acute human serum samples by a quantitative real-time RT-PCR assay

2007 ◽  
Vol 140 (1-2) ◽  
pp. 43-48 ◽  
Author(s):  
Amy J. Lambert ◽  
Olga Kosoy ◽  
Jason O. Velez ◽  
Brandy J. Russell ◽  
Robert S. Lanciotti
Keyword(s):  
Human Serum ◽  
Real Time ◽  
Viral Rna ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serum Samples ◽  
Human Serum Samples

A multifunctional electrochemical sensor for the simultaneous detection of ascorbic acid, dopamine, uric acid, and nitrite

2020 ◽  
Author(s):  
Huimin Wang ◽  
Xueli Zhang ◽  
Shuangjue Wang ◽  
Hanyue Ma ◽  
Xia Wang
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Human Serum ◽  
Electrochemical Sensor ◽  
Chronic Diseases ◽  
Metabolic Disorders ◽  
Simultaneous Detection ◽  
Serum Samples ◽  
Buffer Solution ◽  
Human Serum Samples

Abstract Background Ascorbic acid (AA), dopamine (DA), uric acid (UA), and nitrite (NO2−) are essential biomarkers for human metabolism, and can be used to indicate some chronic diseases and metabolic disorders, including scurvy, Parkinson’s disease, hyperuricemia, and kidney disease. Objective A multifunctional electrochemical sensor that can integrate the detection of these species was constructed using nanoporous gold (NPG) as a recognition element to modify glassy carbon electrode (GCE). Methods The electrochemical performance of the multifunctional electrochemical sensor was investigated toward AA, DA, UA, and NO2− in citrate buffer solution (CBS, 100 mM, pH 4.0) and human serum using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Results In the quaternary mixture detection, the resulting NPG/GCE electrode displayed four independent oxidation peaks with wide peak separations. Further, the NPG/GCE electrode showed good linear responses with the sensitivities of 32, 1103, 71, and 147 μA/mM/cm2 and the detection limits of 1.58, 0.17, 0.37, and 0.36 μM for AA, DA UA, and NO2−, respectively. Additionally, the NPG/GCE electrode exhibited great anti-interference and was successfully applied in human serum samples. Conclusions These results indicate that the NPG/GCE electrode can simultaneously and selectively detect AA, DA, UA, and NO2−, which has the potential for application and diagnosis in the screening and diagnosis of chronic diseases and metabolic disorders. Highlights A multianalyte electrochemical sensor was fabricated for human metabolites detection. The sensor displayed good performance in the simultaneous detection of AA, DA, UA, and NO2−, and applied to human serum samples.

A DNAzyme-based label-free fluorescent probe for guanosine-5′-triphosphate detection

The Analyst ◽  
2020 ◽  
Vol 145 (21) ◽  
pp. 6948-6954
Author(s):  
Chengzhen Hu ◽  
Kemei Jiang ◽  
Zihao Shao ◽  
Minqing Shi ◽  
Hong-Min Meng
Keyword(s):  
Human Serum ◽  
Fluorescent Probe ◽  
Label Free ◽  
Serum Samples ◽  
Human Serum Samples

A DNAzyme-based fluorescent probe with self-phosphorylation ability for label-free and sensitive GTP detection in buffer and human serum samples.

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