scholarly journals Developing Gold Nanoparticles-Conjugated Aflatoxin B1 Antifungal Strips

2019 ◽  
Vol 20 (24) ◽  
pp. 6260 ◽  
Author(s):  
Tobiloba Sojinrin ◽  
Kangze Liu ◽  
Kan Wang ◽  
Daxiang Cui ◽  
Hugh J. Byrne ◽  
...  
Keyword(s):  
Detection Limit ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Point Of Care ◽  
Colour Change ◽  
Food Samples ◽  
Lateral Flow ◽  
Resonance Spectroscopy ◽  
Immunochromatographic Strip ◽  
Specificity And Sensitivity

Lateral flow immunochromatographic assays are a powerful diagnostic tool for point-of-care tests, based on their simplicity, specificity, and sensitivity. In this study, a rapid and sensitive gold nanoparticle (AuNP) immunochromatographic strip is produced for detecting aflatoxin B1 (AFB1) in suspicious fungi-contaminated food samples. The 10 nm AuNPs were encompassed by bovine serum albumin (BSA) and AFB1 antibody. Thin-layer chromatography, gel electrophoresis and nuclear magnetic resonance spectroscopy were employed for analysing the chemical complexes. Various concentrations of AFB1 antigen (0–16 ng/mL) were tested with AFB1 antibody–BSA–AuNPs (conjugated AuNPs) and then analysed by scanning electron microscopy, ultraviolet–visible spectroscopy, and Zetasizer. The results showed that the AFB1 antibody was coupled to BSA by the N-hydroxysuccinimide ester method. The AuNPs application has the potential to contribute to AFB1 detection by monitoring a visible colour change from red to purple-blue, with a detection limit of 2 ng/mL in a 96-well plate. The lateral flow immunochromatographic strip tests are rapid, taking less than 10 min., and they have a detection capacity of 10 ng/g. The smartphone analysis of strips provided the results in 3 s, with a detection limit of 0.3 ng/g for AFB1 when the concentration was below 10 ng/g. Excellent agreement was found with AFB1 determination by high-performance liquid chromatography in the determination of AFB1 among 20 samples of peanuts, corn, rice, and bread.

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

scholarly journals Application of Loop-Mediated Isothermal Amplification combined with colorimetric and lateral flow dipstick visualization as the potential point-of-care testing for diphtheria

2019 ◽  
Author(s):  
Aleksandra Anna Zasada ◽  
Aldona Wiatrzyk ◽  
Urszula Czajka ◽  
Klaudia Brodzik ◽  
Kamila Formińska ◽  
...  
Keyword(s):  
Detection Limit ◽  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Lamp Assay ◽  
Corynebacterium Diphtheriae ◽  
Lateral Flow ◽  
Isothermal Amplification ◽  
Suspected Case ◽  
Point Of Care Testing ◽  
Loop Mediated Isothermal Amplification

Abstract Background Diphtheria outbreaks occurred in endemic areas and imported and indigenous cases are reported in UE/EEA. Because of the high infectiveness and severity of the disease, early and accurate diagnosis of each suspected case is essential for the treatment and management of the case and close contacts. The aim of the study was to establish simple and rapid testing methods based on Loop-Mediated Isothermal Amplification (LAMP) assay for the detection of Corynebacterium diphtheriae and differentiation between toxigenic and non-toxigenic strains.Methods Corynebacterium diphtheriae and Corynebacterium ulcerans isolates from the National Institute of Public Health-National Institute of Hygiene collection were used for the development of LAMP assay for the diagnosis of diphtheria and nontoxigenic C. diphtheriae infections. Various colorimetric methods for visualization of results were investigated. Sensitivity and specificity of the assay were examined using a collection of DNA samples from various gram-positive and gram-negative bacteria.Results The LAMP assay for tox and dtxR genes was developed. The sensitivity and specificity of the assay were calculated as 100%. The detection limit was estimated as 1.42 pg/µl concentration of DNA template when the reaction was conducted for 60 min. However, the detection limit was lowered 10 times for every 10 minutes of reduction in the time of incubation during the reaction. Positive results were successfully detected colorimetrically using hydroxynaphthol blue, calcein, QuantiFluor, and lateral flow Milenia HybriDetect dipsticks.Conclusion The assay developed in the study might be applied for point-of-care testing of diphtheria and other C. diphtheriae infections. It is highly sensitive, specific, inexpensive, easy to use, and suitable for low-resource settings.

scholarly journals A new lateral flow assay to detect sIL-2R during T-cell mediated rejection after kidney transplantation

The Analyst ◽  
2021 ◽  
Author(s):  
Lisa K. Seiler ◽  
Rebecca Jonczyk ◽  
Patrick Lindner ◽  
Ncog Linh Phung ◽  
Christine S. Falk ◽  
...  
Keyword(s):  
Kidney Transplantation ◽  
T Cell ◽  
Point Of Care ◽  
High Specificity ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Point Of Care Test ◽  
Specificity And Sensitivity ◽  
Kidney Rejection ◽  
Acute Kidney Rejection

In this work a novel point of care test to detect sIL-2R during acute kidney rejection with high specificity and sensitivity was developed.

scholarly journals Lateral Flow Immunoassay for Naked Eye Detection of Mycobacterium tuberculosis

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Nazifah Ariffin ◽  
Nor Azah Yusof ◽  
Jaafar Abdullah ◽  
Siti Fatimah Abd Rahman ◽  
Nurul Hanun Ahmad Raston ◽  
...  
Keyword(s):  
Developing Countries ◽  
Mycobacterium Tuberculosis ◽  
Point Of Care ◽  
Colour Change ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Optical Signals ◽  
Naked Eye ◽  
User Friendly ◽  
And Control

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassay (LFIA) has been introduced as a handheld immunoassay-based point-of-care platform for an automated detection of TB. The CFP10-ESAT6 antigen of M. tuberculosis was used as the target in early detection of TB using LFIA strip-based POC strategy. An interesting platform based on optical signals is implemented as a colour change in the detection area that is visible to the naked eye. The gold nanoparticles (AuNPs) were used as the colour probe for the detection of a target of interest. The high-resolution transmission electron microscopy (HRTEM) image and ultraviolet-visible spectrophotometer (UV-Vis) analysis confirmed that the synthesized AuNPs were appropriate for the immunoassay designed. The platform consists of AuNPs conjugated with specific antibodies (Ab) to capture the antigen of M. tuberculosis. Under the capillary effect, sandwich immunoreactions of AuNP-Ab-antigen were performed on the test pad of the immunostrip, which can be observed by the colour signal on the test line of the strip with a short assay time. Furthermore, the newly developed biosensor was utilized in CFP10-ESAT6 antigen detection in human sputum specimens with satisfactory results. The characteristic coloured bands enable visual detection (naked eye) of target analyte without instrumentation. This noninvasive diagnose system which is sputum-based detection could provide user-friendly and affordable diagnostic tests in developing countries.

scholarly journals Analytical performances of the COVISTIX and Panbio antigen rapid tests for SARS-CoV-2 detection in an unselected population (all commers)

2021 ◽  
Author(s):  
Francisco Garcia-Cardenas ◽  
Alba Franco ◽  
Ricardo Cortes ◽  
Jenny Bertin ◽  
Rafael Valdez ◽  
...  
Keyword(s):  
High Performance ◽  
Close Contact ◽  
Point Of Care ◽  
Steady Increase ◽  
Antigen Test ◽  
Rt Pcr ◽  
Viral Shedding ◽  
Specificity And Sensitivity ◽  
Asymptomatic Patients ◽  
Unselected Population

Importance: A steady increase in acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases worldwide is causing some regions of the world to withstand a third or even fourth wave of contagion. Swift detection of SARS-CoV-2 infection is paramount for the containment of cases, prevention of sustained contagion; and most importantly, for the reduction of mortality. Objective: To evaluate the performance and validity of the COVISTIXTM rapid antigen test, for the detection of SARS-CoV-2 in an unselected population and compare it to PanbioTM rapid antigen test and RT-PCR. Design: This is comparative effectiveness study; samples were collected at two point-of-care facilities in Mexico City between May and August 2021. Participants: Recruited individuals were probable COVID-19 cases, either symptomatic or asymptomatic persons that were at risk of infection due to close contact to SARS-CoV-2 positive cases. Diagnostic intervention: RT-PCR was used as gold standard for detection of SARS-CoV-2 in nasal and nasopharyngeal swabs, study subjects were tested in parallel either with the COVISTIXTM or with PanbioTM rapid antigen test. Main outcome: Diagnostic performance of the COVISTIXTM assay is adequate in all commers since its accuracy parameters were not affected in samples collected after 7 days of symptom onset, and it detected almost 65% of samples with a Ct-value between 30 and 34. Results: For the population tested with COVISTIXTM (n=783), specificity and sensitivity of the was 96.0% (CI95% 94.0-98.0) and 81% (CI95% 76.0-85.0), as for the PanbioTM (n=2202) population, was 99.0% (CI95%: 0.99-1.00) and 62% (CI%: 58.0-64.0%), respectively. Conclusions and relevance: The COVISTIXTM rapid antigen test shows a high performance in all comers, thus, this test is also adequate for testing patients who have passed the peak of viral shedding or for asymptomatic patients.

scholarly journals A Rapid and Sensitive Fluorescent Microsphere-Based Lateral Flow Immunoassay for Determination of Aflatoxin B1 in Distillers’ Grains

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2109
Author(s):  
Zifei Wang ◽  
Pengjie Luo ◽  
Baodong Zheng
Keyword(s):  
Aflatoxin B1 ◽  
High Performance ◽  
Animal Feed ◽  
Limit Of Detection ◽  
Lateral Flow ◽  
Distillers Grains ◽  
Detection Methods ◽  
Lateral Flow Immunoassay ◽  
Quantitative Detection ◽  
Fluorescent Microsphere

Aflatoxin B1 (AFB1) is a toxic compound naturally produced by the genera Aspergillus. Distillers’ grains can be used as animal feed since they have high content of crude protein and other nutrients. However, they are easily contaminated by mycotoxins, and currently there are no rapid detection methods for AFB1 in distillers’ grains. In this study, a lateral flow immunoassay (LFIA) based on red fluorescent microsphere (FM), is developed for quantitative detection of AFB1 in distillers’ grains. The whole test can be completed within 15 min, with the cut-off value being 25.0 μg/kg, and the quantitative limit of detection (qLOD) being 3.4 μg/kg. This method represents satisfactory recoveries of 95.2–113.0%, and the coefficients of variation (CVs) are less than 7.0%. Furthermore, this technique is successfully used to analyze AFB1 in real samples, and the results indicates good consistency with that of high-performance liquid chromatography (HPLC). The correlation coefficient is found to be greater than 0.99. The proposed test strip facilitates on-site, cost-effective, and sensitive monitoring of AFB1 in distillers’ grains.

Development of Lateral Flow Immunochromatographic Strips for Micropollutant Screening Using Colorants of Aptamer-Functionalized Nanogold Particles, Part II: Experimental Verification with Aflatoxin B1 and Chloramphenicol

2018 ◽  
Vol 101 (5) ◽  
pp. 1408-1414 ◽  
Author(s):  
Shan Zhang ◽  
Shuai Zhao ◽  
Sai Wang ◽  
Jiahui Liu ◽  
Yiyang Dong
Keyword(s):  
Aflatoxin B1 ◽  
Water Samples ◽  
Lateral Flow ◽  
Competitive Reaction ◽  
Immunochromatographic Strip ◽  
Detection Range ◽  
Nanogold Particles ◽  
Thiolated Aptamer ◽  
Cap Analysis ◽  
Optimized Conditions

Abstract Lateral flow immunochromatographic strips based on colorants of aptamer-functionalized nanogold particles were developed for the detection of micropollutants aflatoxin B1 (AFB1) and chloramphenicol (CAP). The lateral flow immunochromatographic strip was based on a competitive reaction of thiolated-aptamer between micropollutants and bio-DNA probe-streptavidin as capture material immobilized at the test line. General crucial parameters that might influence the sensitivity have been systematically investigated. To test the effectiveness and applicability of the optimized conditions, two structurally unrelated micropollutants, that is, AFB1 and CAP, were chosen for detection. In the present study, lateral flow immunochromatographic strips for AFB1 and CAP analysis by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogold in municipal water samples were reported for the first time. With the optimized conditions, the immunochromatographic strip showed a visual LOD of 10 ppb and a quantitative LOD of 1.05 ppb using an immunochromatographic reader for AFB1 detection and a quantitative LOD of 63.4 ppb using an immunochromatographic reader for CAP detection. Furthermore, the sensitive strip provided a good linear detection range of approximately 0–50 ppm for AFB1 detection and a wider liner detection range of approximately 0–160 ppm for CAP detection. Moreover, the immunochromatographic strip provided recovery rates for water samples of 90–110% in the AFB1 analysis and 84–108% in the CAP analysis. The results demonstrated that the immunochromatographic strip has excellent potential for wide applicability and verified that the strip methods for the optimized conditions are applicable to a variety of micropollutants. The lateral flow immunochromatographic strip could be used as a simple, rapid, and efficient screening tool for rapid on-site detection of a variety of micropollutants.

Immunochromatographic strip assay for the rapid and sensitive detection ofSalmonellaTyphimurium in artificially contaminated tomato samples

2014 ◽  
Vol 60 (6) ◽  
pp. 399-406 ◽  
Author(s):  
Shruti Shukla ◽  
Hyerim Leem ◽  
Jong-Suk Lee ◽  
Myunghee Kim
Keyword(s):  
Detection Limit ◽  
Salmonella Typhimurium ◽  
Food Samples ◽  
Sensitive Detection ◽  
Practical Application ◽  
Immunochromatographic Strip ◽  
Serovar Typhimurium ◽  
Peptone Water ◽  
Colloidal Gold Nanoparticle ◽  
Positive Results

This study was designed to confirm the applicability of a liposome-based immunochromatographic assay for the rapid detection of Salmonella enterica subsp. enterica serovar Typhimurium (Salmonella Typhimurium) in artificially contaminated tomato samples. To determine the detection limit and pre-enrichment incubation time (10, 12, and 18 h pre-enrichment in 1% buffered peptone water), the tests were performed with different cell numbers of Salmonella Typhimurium (3 × 100, 3 × 101, 3 × 102, and 3 × 103CFU·mL−1) inoculated into 25 g of crushed tomato samples. The assay was able to detect as few as 30 Salmonella Typhimurium cells per 25 g of tomato samples (1.2 cells·g−1) after 12 h pre-enrichment incubation. Moreover, when the developed assay was compared with traditional morphological and biochemical culture-based methods as well as colloidal gold nanoparticle-based commercial test strips, the developed assay yielded positive results for the detection of Salmonella Typhimurium within a shorter period time. These findings confirm that the developed assay may have practical application for the sensitive detection of Salmonella Typhimurium in various food samples, including raw vegetables, with a relatively low detection limit and shorter analysis time.

scholarly journals Direct comparison of venipuncture serum draws versus whole blood finger-stick specimens by anti-COVID-19 IgG/IgM rapid lateral flow immunoassay and ELISA.

2021 ◽  
Author(s):  
Irfan Baig ◽  
Christian Tagwerker ◽  
Eric J. Brunson ◽  
Kristine Mundo ◽  
Davan Dutra-Smith ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Test Results ◽  
Sample Collection ◽  
Igm Antibodies ◽  
Specificity And Sensitivity ◽  
Qualitative Test ◽  
Finger Stick

During the COVID-19 pandemic, manufacturers have developed several diagnostic test kits that include lateral flow immunoassays (LFIA) also known as rapid cassette testing. Rapid cassette testing provides qualitative test results indicating the presence or absence of IgG and IgM antibodies to determine COVID-19 (SARS-CoV-2) infection among individuals. Venipuncture blood draws have been the traditional and widely proposed sample collection method but is costly and not applicable to point-of-care testing (POC) and in remote settings. Whole blood finger-stick blood collections traditionally used by diabetics for glucose level testing is an ideal scenario, but raises concerns regarding the outcome of test results in regards to specificity and sensitivity. In this study we directly compare simultaneous collections of venipuncture serum (SST) blood draws and whole blood finger-sticks (n = 75) to detect human Anti-COVID-19 IgG and IgM antibodies using an EUA-approved lateral flow immunoassay, showing equal to enhanced performance characteristics for this specimen type.

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