Rapid immunoassays for detection of anabolic nortestosterone in dietary supplements

An enzyme immunoassay (ELISA) and an immunochromatographic strip were designed for a rapid detection of nortestosterone in dietary supplements. Two polyclonal antibodies and two types of nortestosterone-protein coating conjugates were tested to develop the most appropriate method. Under optimal experimental conditions, the most sensitive ELISA achieved the IC<sub>50 </sub>and the limit of detection values of 6.41 and 0.09 ng/ml, respectively. The assay specificity was tested measuring cross-reactivity of several steroids. The interference with the assay was negligible (< 0.1%), except for cross-reactivity with another frequently abused steroid testosterone (23%). The optimised gold particle-based immunochromatographic strip provided in semi-quantitative test a visual detection limit of 1 ng/ml. None of these methods showed the interference using a filtrate of the suspension of non-contaminated sample. After the validation for particular matrices, the ELISA and the strip test could be useful tools for a rapid analysis of nortestosterone in crude extracts of dietary supplements.

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Development of an antigen-ELISA and a colloidal gold–based immunochromatographic strip based on monoclonal antibodies for detection of avian influenza A(H5) viruses

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211027538 ◽

2021 ◽

pp. 104063872110275

Author(s):

Yixin Xiao ◽

Fan Yang ◽

Fumin Liu ◽

Linfang Cheng ◽

Hangping Yao ◽

...

Keyword(s):

Avian Influenza ◽

Disease Virus ◽

Colloidal Gold ◽

Rapid Detection ◽

Influenza A ◽

Field Investigation ◽

Cross Reactivity ◽

Detection Methods ◽

Immunochromatographic Strip ◽

Antigen Elisa

Avian influenza A(H5) viruses (avian IAVs) pose a major threat to the economy and public health. We developed an antigen-ELISA (ag-ELISA) and a colloidal gold–based immunochromatographic strip for the rapid detection of avian A(H5) viruses. Both detection methods displayed no cross-reactivity with other viruses (e.g., other avian IAVs, infectious bursal disease virus, Newcastle disease virus, infectious bronchitis virus, avian paramyxovirus). The ag-ELISA was sensitive down to 0.5 hemagglutinin (HA) units/100 µL of avian A(H5) viruses and 7.5 ng/mL of purified H5 HA proteins. The immunochromatographic strip was sensitive down to 1 HA unit/100 µL of avian A(H5) viruses. Both detection methods exhibited good reproducibility with CVs < 10%. For 200 random poultry samples, the sensitivity and specificity of the ag-ELISA were 92.6% and 98.8%, respectively, and for test strips were 88.9% and 98.3%, respectively. Both detection methods displayed high specificity, sensitivity, and stability, making them suitable for rapid detection and field investigation of avian A(H5) viruses.

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Immunochromatographic Strip Test for Rapid Detection of Nevirapine in Plasma Samples from Human Immunodeficiency Virus-Infected Patients

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00445-07 ◽

2007 ◽

Vol 51 (9) ◽

pp. 3361-3363 ◽

Cited By ~ 6

Author(s):

Tim R. Cressey ◽

Sawitree Nangola ◽

Yardpiroon Tawon ◽

Mookda Pattarawarapan ◽

Marc Lallemant ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Limit Of Detection ◽

Drug Level ◽

Plasma Samples ◽

Immunochromatographic Strip ◽

Resource Limited ◽

Qualitative Detection ◽

Immunodeficiency Virus ◽

Immunochromatographic Strip Test ◽

Strip Test

ABSTRACT We report a novel one-step immunochromatographic strip test for the rapid, qualitative detection of nevirapine in plasma samples from human immunodeficiency virus-infected patients. The sensitivity was 100% (95% confidence interval [95% CI], 97.8 to 100%), and the specificity was 99.5% (95% CI, 97.2 to 99.9%). The limit of detection was 25 ng/ml. Immunochromatographic strip tests are simple, rapid, and cheap assays that could greatly facilitate drug level monitoring in resource-limited settings.

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Development of an Immunochromatographic Strip Test for Rapid Detection of Melamine in Raw Milk, Milk Products and Animal Feed

Journal of Agricultural and Food Chemistry ◽

10.1021/jf2008327 ◽

2011 ◽

Vol 59 (11) ◽

pp. 6064-6070 ◽

Cited By ~ 46

Author(s):

Xiangmei Li ◽

Pengjie Luo ◽

Shusheng Tang ◽

Ross C. Beier ◽

Xiaoping Wu ◽

...

Keyword(s):

Rapid Detection ◽

Animal Feed ◽

Raw Milk ◽

Immunochromatographic Strip ◽

Milk Products ◽

Immunochromatographic Strip Test ◽

Strip Test

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Development of a one-step immunochromatographic strip test for the rapid detection of nevirapine (NVP), a commonly used antiretroviral drug for the treatment of HIV/AIDS

Talanta ◽

10.1016/j.talanta.2006.05.059 ◽

2007 ◽

Vol 71 (1) ◽

pp. 462-470 ◽

Cited By ~ 26

Author(s):

M. Pattarawarapan ◽

S. Nangola ◽

T.R. Cressey ◽

C. Tayapiwatana

Keyword(s):

Rapid Detection ◽

Immunochromatographic Strip ◽

Antiretroviral Drug ◽

One Step ◽

Immunochromatographic Strip Test ◽

Strip Test ◽

Hiv Aids

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Fluorescence Polarization Immunoassay for Determination of Enrofloxacin in Pork Liver and Chicken

Molecules ◽

10.3390/molecules24244462 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4462

Author(s):

Xing Shen ◽

Jiahong Chen ◽

Shuwei Lv ◽

Xiulan Sun ◽

Boris B. Dzantiev ◽

...

Keyword(s):

Fluorescence Polarization ◽

Limit Of Detection ◽

Polyclonal Antibodies ◽

Screening Method ◽

Sample Pretreatment ◽

High Sensitivity ◽

Cross Reactivity ◽

Fluorescence Polarization Immunoassay ◽

Pork Liver ◽

Sensitivity Specificity

Enrofloxacin (ENR) is a widely used fluoroquinolone (FQ) antibiotic for antibacterial treatment of edible animal. In this study, a rapid and highly specific fluorescence polarization immunoassay (FPIA) was developed for monitoring ENR residues in animal foods. First, ENR was covalently coupled to bovine serum albumin (BSA) to produce specific polyclonal antibodies (pAbs). Three fluorescein-labeled ENR tracers (A, B, and C) with different spacers were synthesized and compared to obtain higher sensitivity. Tracer C with the longest arm showed the best sensitivity among the three tracers. The developed FPIA method showed an IC50 (50% inhibitory concentration) of 21.49 ng·mL−1 with a dynamic working range (IC20–IC80) of 4.30–107.46 ng·mL−1 and a limit of detection (LOD, IC10) of 1.68 ng·mL−1. The cross-reactivity (CR) of several structurally related compounds was less than 2%. The recoveries of spiked pork liver and chicken samples varied from 91.3% to 112.9%, and the average coefficients of variation were less than 3.83% and 5.13%, respectively. The immunoassay took only 8 min excluding sample pretreatment. This indicated that the established method had high sensitivity, specificity, and the advantages of simplicity. Therefore, the proposed FPIA provided a useful screening method for the rapid detection of ENR residues in pork liver and chicken.

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