Qiankun Zheng

Development of an immunochromatographic strip for the rapid detection of 10 β-agonists based on an ultrasensitive monoclonal antibody

ABSTRACT A sensitive monoclonal antibody, 3G10, derived from a mouse immunized with an immunogen of salbutamol hapten conjugated to keyhole limpet hemocyanin was developed against β-agonists, with a view to establishing a rapid gold nanoparticle immunochromatographic strip. The antibody displayed a 50% inhibitory concentration (IC50) of 1.04 ng/mL for salbutamol and simultaneously detected nine other β-agonists (clenbuterol, cimatero, brombuterol, mabuterol, terbutaline, clenpenterol, carbuterol, mapenterol, pirbuterol) with uniform cross-reactivity. The immunochromatographic strip had cut-off values of 5 ng/mL for salbutamol and clenbuterol, 20 ng/mL for cimaterol, brombuterol and mabuterol, and 50 ng/mL for terbutaline, clenpenterol, carbuterol, mapenterol and pirbuterol. The collective advantages of the newly developed strip, such as high affinity, sensitivity and rapidity, support its utility in detecting β-agonists from actual biological samples, such as urine.

Rapid detection of aldicarb in cucumber with an immunochromatographic test strip

ABSTRACT A rapid, simple, and sensitive immunochromatographic strip test has been developed to detect aldicarb (ALD) in 0.01 M phosphate buffer solution (PBS) (pH 7.4) and cucumber samples. The test was developed with a sensitive monoclonal antibody specific for ALD, generated by immunizing BALB/c mice with a well-characterized ALD – keyhole limpet hemocyanin conjugate, produced in our laboratory. Under the optimized condition, the cut-off limits of test strip for ALD were found to be 25 ng/mL in 0.01 M PBS (pH 7.4) and 100 ng/mL in cucumber samples, and the highest standard relative deviation was 9.05%. Both results were obtained within 5 min. The data indicate that the method is sensitive, rapid, and specific, so this immunochromatographic test strip has utility for the rapid high-throughput screening of the pesticide, especially in food samples.

Development of an immunochromatographic assay for the detection of alternariol in cereal and fruit juice samples

ABSTRACT An immunochromatographic strip was developed for the determination of alternariol (AOH) using both semi-quantitative and quantitative methods based on a sensitive monoclonal antibody we produced. With AOH-spiked samples, the visual limit of detection for cereal and juice were 160 ng/g and 25 ng/mL, and the cut-off values were 640 ng/g and 100 ng/mL, respectively. For quantitative analysis based on a strip scan reader, the calculated limit of detection was 15.5–19.4 ng/g for cereal and 2.8–3.5 ng/mL for fruit juice. The recovery rates ranged from 116% to 125%, and 113% to 123%, respectively. Therefore, this method was effective for AOH detection and suitable for on-site detection and rapid screening of samples.

Rapid detection of tenuazonic acid in cereal and fruit juice using a lateral-flow immunochromatographic assay strip

ABSTRACT A lateral-flow immunochromatographic assay (ICA) strip was developed for determination of tenuazonic acid (TeA) using both semi-quantitative and quantitative methods. The ICA strip was based on produced anti-TeA monoclonal antibody, and could be used for TeA analysis in cereal and fruit juice, with visual limits of detection of 1600 ng/g and 400 ng/mL, and cut-off values of 6400 ng/g and 3200 ng/mL, respectively. The calculated limits of detection values were 126.4 ng/g and 65.3 ng/mL for wheat and apple juice samples, respectively. The recovery rates ranged from 90% to 129%. In summary, the developed strip was effective for TeA detection and would be suitable for on-site detection and rapid screening of samples.

Preparation of an anti-dexamethasone monoclonal antibody and its use in development of a colloidal gold immunoassay

ABSTRACT A lateral flow colloidal gold (CG) immunoassay strip has been developed for detection of dexamethasone (DEX) residues in milk samples. For this purpose, an anti-DEX monoclonal antibody (McAb), based on a DEX succinic anhydride derivative hapten, was prepared and characterized. The McAb showed a high specificity to DEX, the half inhibitory concentration of the antibody was 0.095 ng/mL, its limit of detection (LOD) was 0.017 ng/mL, and its linear range of detection was 0.034–0.265 ng/mL. The developed CG immunoassay had a visual cut-off value of 0.3 ng/mL in phosphate buffered saline (PBS) and 0.5 ng/mL in milk samples. Each test requires 10 min. Analysis of DEX in milk indicated that the results of strip assay had a strong agreement with indirect competitive enzyme-linked immunosorbent assay. Therefore, the CG immunoassay is a sensitive screening method for semi-quantitative and qualitative detection of DEX residues in milk samples.

Development of an antibody-based colloidal gold immunochromatographic lateral flow strip test for natamycin in milk and yoghurt samples

ABSTRACT An immunochromatographic lateral flow strip test was developed for the detection of natamycin (Nata) residues in milk and cheese samples. Monoclonal antibody (mAb) against Nata was produced with a half maximal inhibitory concentration of 1.85 μg L−1. MAb conjugated with gold nanoparticles was the detection reagent. Nata conjugated with ovalbumin via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide method immobilized on a nitrocellulose membrane was the capture reagent. This semi-quantitative method required only 15 min to complete. The optimum concentrations of coating antigen and mAb were 0.15 µg mL−1 and 0.2 µg mL−1, respectively. Based on an optical density scanner, the visual limit of detection of Nata was 5 μg L−1 and 10 μg kg−1 in milk and yoghurt samples, respectively.

Development of an immunochromatographic test strip for the detection of papaverine in pure ginger powder

ABSTRACT A leteral-flow immunochromatographic assay was developed for the detection of papaverine (PAPA) in pure ginger powder samples. We produced a sensitive monoclonal antibody againsts PAPA (anti-PAPA mAb) by immunizing BALB/c mice with a well-characterized PAPA-keyhole limpet hemocyanin conjugate, produced in our laboratory. The coating antigen (PAPA-ovalbumin) and goat anti-mouse IgG antibody were used as the capture reagent in the control line of the test strip. Under optimized conditions, the cut-off limits of the test strip was 1 ng/mL in 0.01 M PBS (pH 7.4) and 5 ng/mL in pure ginger powder. The results were obtained within 5 min. The results revealed that the developed method is a sensitive, rapid, and simple tool for the detection of PAPA in pure ginger powder.

Rapid detection of clonidine and its cross-reactivity with apraclonidine in pig urine using an immunochromatographic test strip

ABSTRACT Clonidine (CLO) preferentially stimulates central α-2-adrenoceptors and causes both desirable and undesirable effects. Undesirable effects include sedation and withdrawal reactions, which occur as a sudden rise in arterial pressure, nervousness, agitation, and increased heart rate. An immunochromatographic test strip was developed for the rapid simultaneous detection of CLO and its cross-reactivity with apraclonidine (ACLO) in pig urine. The antigen CLO-OVA and goat anti-mouse IgG were attached to a nitrocellulose membrane as control line and test line. The cut-off limits of the test strips for CLO and ACLO were found to be 2.5 ng/mL in both 0.01 M PBS (pH 7.4) and pig urine. All the results were obtained within 5 min. The results revealed that the developed method is a sensitive, rapid, and simple tool for the detection of CLO and ACLO.

Development of an immunochromatographic strip for detection of acetamiprid in cucumber and apple samples

ABSTRACT An immunochromatographic strip was developed for detection of acetamiprid (AC) and cross-reactivity with thiacloprid (TC) in cucumber and apple samples. This detection system was developed based on a sensitive and specific monoclonal antibody produced in our laboratory. Under optimized conditions, the cut-off limits of the test strip for AC were found to be 1 and 0.25 ng/mL for TC in phosphate-buffered saline. Meanwhile, with simple preparation for detection cucumber and apple samples, the cut-off limits for AC were found to be 5 and 2.5 ng/mL for TC in cucumber samples. The immunochromatographic assay also revealed AC cut-off values of 30 and 15 ng/mL in apple samples. Each test can be evaluated within 5 min. The data indicate that the method is sensitive, rapid, specific, and has the advantages of simplicity; therefore, this immunochromatographic assay is a useful screening method for detection of AC and TC residues in cucumber and apple samples.

Ultrasensitive and eco-friendly immunoassays based monoclonal antibody for detection of deoxynivalenol in cereal and feed samples

Ultrasensitive immunoassays, including an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and a lateral-flow immunochromatographic assay (ICA), were developed based on a monoclonal antibody for the analysis of deoxynivalenol in food and feed samples. With 0.01 M PBS, 20% ethanol-PBS, and 60% ethanol-PBS extraction, which are environmentally safe, the 50% inhibitory concentration (IC50) and limit of detection (LOD) values were 1.83-4.68 μg/kg and 0.241-0.664 μg/kg, respectively, with recovery rates of 87.7%-137% and coefficient variation values of 3.99-9.88% (intra-assay) and 4.17-9.81% (inter-assay) for the ic-ELISA relative to the results obtained by liquid chromatography-tandem mass spectrometry (LC-MS). For the ICA strip, the visual LODs were 10-150 μg/kg, the cut-off values were 50-750 μg/kg, and the calculated LODs were 1.97-46.8 μg/kg, with different sample extraction solutions, and the recovery rates were 66.7%-127%. These methods are sensitive, simple and safe, providing an auxiliary analytical tool for screening the massive samples in markets.