scholarly journals Polystyrene Microsphere-Based Immunochromatographic Assay for Detection of Aflatoxin B1 in Maize

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 200
Author(s):  
Jin Wang ◽  
Xiangmei Li ◽  
Xing Shen ◽  
Ang Zhang ◽  
Jinxiu Liu ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Point Of Care Testing ◽  
Polystyrene Microsphere ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Liquid Chromatography Tandem Mass

Aflatoxin B1 (AFB1), a mycotoxin, is hepatotoxic, carcinogenic, and nephrotoxic in humans and animals, and contaminate a wide range of maize. In this study, an immunochromatographic assay (ICA) based on polystyrene microspheres (PMs) was developed for sensitive and quantitative detection of AFB1 in maize. The amounts of PMs, the condition for activating carboxyl groups of PMs, the amount of monoclonal antibody (mAb), and the volume of the immune probe were optimized to enhance the performance PMs-ICA for point-of-care testing of AFB1 in maize. The PMs-ICA showed the cut-off value of 1 ng/mL in phosphate buffer (PB) and 6 µg/kg in maize samples, respectively. The quantitative limit of detection (qLOD) was 0.27 and 1.43 µg/kg in PB and maize samples, respectively. The accuracy and precision of the PMs-ICA were evaluated by analysis of spiked maize samples with recoveries of 96.0% to 107.6% with coefficients of variation below 10%. In addition, the reliability of PMs-ICA was confirmed by the liquid chromatography-tandem mass spectrometry method. The results indicated that the PMs-ICA could be used as a sensitive, simple, rapid point-of-care testing of AFB1 in maize.

scholarly journals PERFORMANCE CHARACTERISTICS OF A FRET-BASED IMMUNOASSAY FOR QUANTITATION OF INFLIXIMAB ON A POINT-OF-CARE INSTRUMENT SYSTEM

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S57-S57
Author(s):  
Edgar Ong ◽  
Ruo Huang ◽  
Richard Kirkland ◽  
Michael Hale ◽  
Larry Mimms
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Hook Effect ◽  
Limit Of Quantitation ◽  
Assay Precision

Abstract Introduction A fast (<5 min), time-resolved fluorescence resonance energy transfer (FRET)-based immunoassay was developed for the quantitative detection of infliximab (IFX) and biosimilars for use in therapeutic drug monitoring using only 20 µL of fingerstick whole blood or serum at the point-of-care. The Procise IFX assay and ProciseDx analyzer are CE-marked. Studies were performed to characterize analytical performance of the Procise IFX assay on the ProciseDx analyzer. Methods Analytical testing was performed by spiking known amounts of IFX into negative serum and whole blood specimens. Analytical sensitivity was determined using limiting concentrations of IFX. Linearity was determined by testing IFX across the assay range. Hook effect was assessed at IFX concentrations beyond levels expected to be found within a patient. Testing of assay precision, cross-reactivity and potential interfering substances, and biosimilars was performed. The Procise IFX assay was also compared head-to-head with another CE-marked assay: LISA-TRACKER infliximab ELISA test (Theradiag, France). The accuracy of the Procise IFX assay is established through calibrators and controls traceable to the WHO 1st International Standard for Infliximab (NIBSC code: 16/170). Results The Procise IFX assay shows a Limit of Blank, Limit of Detection, and Lower Limit of Quantitation (LLoQ) of 0.1, 0.2, and 1.1 µg/mL in serum and 0.6, 1.1, and 1.7 µg/mL in whole blood, respectively. The linear assay range was determined to be 1.7 to 77.2 µg/mL in serum and whole blood. No hook effect was observed at an IFX concentration of 200 µg/mL as the value reported as “>ULoQ”. Assay precision testing across 20 days with multiple runs and reagent lots showed an intra-assay coefficient of variation (CV) of 2.7%, an inter-assay CV of <2%, and a total CV of 3.4%. The presence of potentially interfering/cross-reacting substances showed minimal impact on assay specificity with %bias within ±8% of control. Testing of biosimilars (infliximab-dyyb and infliximab-abda) showed good recovery. A good correlation to the Theradiag infliximab ELISA was obtained for both serum (slope=1.01; r=0.99) and whole blood (slope=1.01; r=0.98) samples (Figure 1). Conclusion Results indicate that the Procise IFX assay is sensitive, specific, and precise yielding results within 5 minutes from both whole blood and serum without the operator needing to specify sample type. Additionally, it shows very good correlation to a comparator assay that takes several hours and sample manipulation to yield results. This makes the Procise IFX assay ideal for obtaining fast and accurate IFX quantitation, thus allowing for immediate drug level dosing decisions to be made by the physician during patient treatment.

scholarly journals A Smartphone Camera Colorimetric Assay of Acetylcholinesterase and Butyrylcholinesterase Activity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1796
Author(s):  
Miroslav Pohanka ◽  
Jitka Zakova
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Specific Treatment ◽  
Point Of Care Testing ◽  
Analytical Instruments ◽  
Colorimetric Test ◽  
3D Printed ◽  
Butyrylcholinesterase Activity ◽  
Additional Education

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can serve as biochemical markers of various pathologies like liver disfunction and poisonings by nerve agents. Ellman’s assay is the standard spectrophotometric method to measure cholinesterase activity in clinical laboratories. The authors present a new colorimetric test to assess AChE and BChE activity in biological samples using chromogenic reagents, treated 3D-printed measuring pads and a smartphone camera as a signal detector. Multiwell pads treated with reagent substrates 2,6-dichlorophenolindophenyl acetate, indoxylacetate, ethoxyresorufin and methoxyresorufin were prepared and tested for AChE and BChE. In the experiments, 3D-printed pads containing indoxylacetate as a chromogenic substrate were optimal for analytical purposes. The best results were achieved using the red (R) channel, where the limit of detection was 4.05 µkat/mL for BChE and 4.38 µkat/mL for AChE using a 40 µL sample and a 60 min assay. The major advantage of this method is its overall simplicity, as samples are applied directly without any specific treatment or added reagents. The assay was also validated to the standard Ellman’s assay using human plasma samples. In conclusion, this smartphone camera-based colorimetric assay appears to have practical applicability and to be a suitable method for point-of-care testing because it does not require specific manipulation, additional education of staff or use of sophisticated analytical instruments.

scholarly journals Wave-shaped microfluidic chip assisted point-of-care testing for accurate and rapid diagnosis of infections

2021 ◽  
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Mingzhu Yang ◽  
Changcheng Qian ◽  
A S M Muhtasim Fuad Sohan
Keyword(s):  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Simultaneous Detection ◽  
Accurate Diagnosis ◽  
Point Of Care Testing ◽  
Promising Alternative ◽  
Reactive Protein ◽  
Linear Relationships ◽  
Multiple Biomarkers

Abstract Background: Simultaneous and timely detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) provides effective information for the accurate diagnosis of infections. Early diagnosis and classification of infections increase the cure rate while decreasing complications, which is significant for severe infections, especially for war surgery. However, traditional methods rely on laborious operations and bulky devices. On the other hand, point-of-care (POC) methods suffer from limited robustness and accuracy. Therefore, it is of urgent demand to develop POC devices for rapid and accurate diagnosis of infections to fulfill on-site militarized requirements.Methods: We developed a wave-shaped microfluidic chip (WMC) assisted multiplexed detection platform (WMC-MDP). WMC-MDP reduces detection time and improves repeatability through premixing of the samples and reaction of the reagents. We further combined the detection platform with the streptavidin-biotin (SA-B) amplified system to enhance the sensitivity while using chemiluminescence (CL) intensity as signal readout. We realized simultaneous detection of CRP, PCT, and IL-6 on the detection platform and evaluated the sensitivity, linear range, selectivity, and repeatability. Finally, we finished detecting 15 samples from volunteers and compared the results with commercial ELISA kits.Results: Detection of CRP, PCT, and IL-6 exhibited good linear relationships between CL intensities and concentrations in the range of 1.25-40 μg/mL, 0.4-12.8 ng/mL, and 50-1600 pg/mL. The limit of detection (LOD) of CRP, PCT, and IL-6 were 0.54 μg/mL, 0.11 ng/mL, and 16.25 pg/mL, respectively. WMC-MDP is capable of good adequate selectivity and repeatability. The whole detection procedure takes only 22 minutes that meets the requirements of a POC device. Results of 15 samples from volunteers were consistent with the results detected by commercial ELISA kits.Conclusion: WMC-MDP allows simultaneous, rapid, and sensitive detection of CRP, PCT, and IL-6 with satisfactory selectivity and repeatability, requiring minimal manipulation. However, WMC-MDP takes advantage of being a microfluidic device showing the coefficients of variation less than 10% enabling WMC-MDP to be a type of POCT. Therefore, WMC-MDP provides a promising alternative to point-of-care testing (POCT) of multiple biomarkers. We believe the practical application of WMC-MDP in militarized fields will revolutionize infection diagnosis for soldiers.

scholarly journals Antibody Microarray Immunoassay for Simultaneous Quantification of Multiple Mycotoxins in Corn Samples

Toxins ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 415 ◽  
Author(s):  
Xian Zhang ◽  
Zuohuan Wang ◽  
Yun Fang ◽  
Renjie Sun ◽  
Tong Cao ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Aflatoxin B1 ◽  
Goodness Of Fit ◽  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Fumonisin B1 ◽  
Quantitative Detection ◽  
Antibody Microarray ◽  
Test Kit ◽  
Microarray Immunoassay

We developed and tested a prototype of an antibody microarray immunoassay for simultaneous quantitative detection of four typical mycotoxins (aflatoxin B1, ochratoxin A, zearalenone, and fumonisin B1) in corn samples. The test kit consisted of a nitrocellulose membrane layered with immobilized monoclonal antibodies against mycotoxins. During the assay, the mycotoxin-protein conjugates were biotinylated. The signal detection was enhanced by a combination of the biotin-streptavidin system and enhanced chemiluminescence (ECL). This improved the sensitivity of the assay. Under the optimized conditions, four calibration curves with goodness of fit (R2 > 0.98) were plotted. The results showed that the detection limits for aflatoxin B1, ochratoxin A, zearalenone, and fumonisin B1 were 0.21, 0.19, 0.09, and 0.24 ng/mL, with detection ranges of 0.47–55.69, 0.48–127.11, 0.22–31.36, and 0.56–92.57 ng/mL, respectively. The limit of detection (LOD) of this antibody microarray for aflatoxin B1, ochratoxin A, zearalenone, and fumonisin B1 in corn was 5.25, 4.75, 2.25, and 6 μg/kg, respectively. The recovery rates from the spiked samples were between 79.2% and 113.4%, with coefficient of variation <10%. The results of the analysis of commercial samples for mycotoxins using this new assay and the liquid chromatography-tandem mass spectrometry (LC-MS/MS) were comparable and in good agreement. This assay could also be modified for the simultaneous detection of other multiple mycotoxins, as well as low-weight analytes, hazardous to human health.

Paper-based selective and quantitative detection of uric acid using citrate-capped Pt nanoparticles (PtNPs) as a colorimetric sensing probe through a simple and remote-based device

2019 ◽  
Vol 43 (20) ◽  
pp. 7636-7645 ◽  
Author(s):  
Muhsin Ali ◽  
Muhammad Asad Ullah Khalid ◽  
Imran Shah ◽  
Soo Wan Kim ◽  
Young Su Kim ◽  
...  
Keyword(s):  
Uric Acid ◽  
Point Of Care ◽  
Pt Nanoparticles ◽  
Quantitative Detection ◽  
Point Of Care Testing ◽  
Colorimetric Sensing

A colorimetric portable setup was developed for remote UA measurements using a smartphone-based application to demonstrate its use in point-of-care testing.

scholarly journals Performance evaluation of the point-of-care SAMBA II SARS-CoV-2 Test for detection of SARS-CoV-2

2020 ◽  
Author(s):  
Sonny M Assennato ◽  
Allyson V Ritchie ◽  
Cesar Nadala ◽  
Neha Goel ◽  
Hongyi Zhang ◽  
...  
Keyword(s):  
Public Health ◽  
Infection Control ◽  
Sensitivity And Specificity ◽  
Patient Management ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Point Of Care Testing ◽  
Clinical Sensitivity

AbstractNucleic acid amplification for the detection of SARS-CoV-2 RNA in respiratory samples is the standard method for diagnosis. These tests are centralised and therefore turnaround times can be 2-5 days. Point-of-care testing with rapid turnaround times would allow more effective triage in settings where patient management and infection control decisions need to be made rapidly.Inclusivity and specificity of the SAMBA II SARS-CoV-2 assay was determined by in silico analyses of the primers and probes. Analytical and clinical sensitivity and specificity of the SAMBA II SARS-CoV-2 Test was evaluated for analytical sensitivity and specificity. Clinical performance was evaluated in residual clinical samples compared to the Public Health England reference tests.The limit of detection of the SAMBA II SARS-CoV-2 Test is 250 cp/mL and is specific for detection of 2 regions of the SARS-CoV-2 genome. The clinical sensitivity was evaluated in 172 clinical samples provided by the Clinical Microbiology and Public Health Laboratory, Addenbrooke’s Hospital, Cambridge (CMPHL), which showed a sensitivity of 98.9% (95% CI 94.03-99.97%), specificity of 100% (95% CI 95.55-100%), PPV of 100% and NPV of 98.78% (92.02-99.82%) compared to testing by CMPHLSAMBA detected 3 positive samples that were initially negative by PHE Test. The data shows that the SAMBA II SARS-CoV-2 Test performs equivalently to the centralised testing methods with a much quicker turnaround time. Point of care testing, such as SAMBA, should enable rapid patient management and effective implementation of infection control measures.

scholarly journals Analysis: Investigating the quality of POCT devices for HbA1c, what are our next steps?

2019 ◽  
Vol 13 (6) ◽  
pp. 1154-1157 ◽  
Author(s):  
Erna Lenters-Westra ◽  
Emma English
Keyword(s):  
Point Of Care ◽  
Performance Evaluations ◽  
Clinical Settings ◽  
Point Of Care Testing ◽  
Performance History ◽  
Future Studies ◽  
Wide Range ◽  
Need To Evaluate ◽  
Number Of Publications

There are a growing number of publications evaluating the performance of HbA1c point-of-care testing (POCT) devices when compared to routine laboratory instruments, but is this what we need from future studies? Here we describe the current understanding of the performance of POCT for HbA1c, which areas need further studies, and the key requirements for future publications based on performance evaluations of these devices. These include studies in clinical settings, performance measured against internationally standardized reference methods, and the need to evaluate new to the market devices that do not currently have a detailed performance history. In addition we highlight the need for external quality assessment schemes that are designed to support POCT in a wide range of clinical settings.

scholarly journals Cost-Effective Flexible CSRR-Based Sensor for Noninvasive Measurement of Permittivity of Biomaterials

2021 ◽  
Vol 10 (1) ◽  
pp. 26
Author(s):  
Faezeh Shanehsazzadeh ◽  
Nafise Azizi ◽  
Hosna Kazerooni Haghighat ◽  
Fatemeh Mashayekhi ◽  
Mehdi Fardmanesh
Keyword(s):  
Ring Resonator ◽  
Point Of Care ◽  
Cost Effective ◽  
Split Ring Resonator ◽  
Point Of Care Testing ◽  
Split Ring ◽  
Tissue Samples ◽  
Complementary Split Ring Resonator ◽  
Microwave Sensor ◽  
Wide Range

A novel, cost-effective, flexible microwave sensor is proposed to facilitate point-of-care testing (POCT) methods for medical diagnosis. The sensor is based on the complementary split-ring resonator (CSRR) to accurately measure the permittivity of biomaterials over a wide range of frequencies. This ability can be used to characterize various materials under test (MUT) such as blood, saliva, tissue samples, etc. The flexibility of the proposed sensor means that it can be used when the accessibility of the sample has technical difficulties, such as on curved surfaces. Firstly, the optimized structure and coupling to the readout transmission line are evaluated using finite element method (FEM) simulations. Then, the prototype of the optimized structure is fabricated on a thin polydimethylsiloxane (PDMS) substrate as a biocompatible economical polymer, and aluminium is carefully chosen for the fabrication of CSRR and readout parts. The proposed flexible sensor is tested and compared to conventional rigid CSRR sensors. The proposed structure withstood the different bending positions well, and also showed an improvement in the results for curved MUT.

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