Yangying Sun1, Tian Fu1, Shuxian Chen1, Zhen Wu1, Yuxing Guo2, Daodong Pan1,2, Ning Gan3. 1. Animal Protein Food Processing Technology Laboratory of Zhejiang Province, Ningbo University, No 169 Qixing South Road, Meishan Bonded Port Area, Ningbo, P. R. China. 2. Food Science & Nutrition Department, Ginling College, Nanjing Normal University, No 122 Ninghai Road, Gulou District, Nanjing, P. R. China. 3. Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, People's Republic of China.
Abstract
BACKGROUND: A novel colorimetric immunosensor was developed for the simple, sensitive and selective detection of ractopamine (RAC) based on using β-cyclodextrin-modified Fe3 O4 particles (Fe3 O4 @β-CD) as capture probes and complex platinum colloid nanoparticles (PtNPs-PV) composed of platinum colloid nanoparticles (PtNPs) and polymerase chelate PowerVision (PV) as signal probes. RESULTS: PtNPs-PV double catalyzed the chromogenic substrate 3,3'-diaminobenzidine (DAB), which induced changes in the color of DAB and chromogenic absorbance. Incubation temperature, pH and incubation time were systematically optimized and, under optimum conditions, the measured absorbance values showed a linear relationship with the RAC concentrations in the range 0.03-8.1 ng mL-1 . The detection limit was 0.01 ng mL-1 . The sensor exhibited high sensitivity and specificity, as demonstrated by testing structurally similar organic compounds such as salbutamol, clenbuterol and dopamine. The practicality of the developed colorimetric immunosensor was supported by the successful detection of RAC in pork samples with recovery ranging from 94.00% to 106.00%. CONCLUSION: We designed a novel sandwich-type noncompetitive colorimetric immunoassay for the detection of trace levels of RAC in pork. The proposed method can also be used for the detection of toxins in food products via PtNPs-PV amplification.
BACKGROUND: A novel colorimetric immunosensor was developed for the simple, sensitive and selective detection of ractopamine (RAC) based on using β-cyclodextrin-modified Fe3 O4 particles (Fe3 O4 @β-CD) as capture probes and complex platinum colloid nanoparticles (PtNPs-PV) composed of platinum colloid nanoparticles (PtNPs) and polymerase chelate PowerVision (PV) as signal probes. RESULTS: PtNPs-PV double catalyzed the chromogenic substrate 3,3'-diaminobenzidine (DAB), which induced changes in the color of DAB and chromogenic absorbance. Incubation temperature, pH and incubation time were systematically optimized and, under optimum conditions, the measured absorbance values showed a linear relationship with the RAC concentrations in the range 0.03-8.1 ng mL-1 . The detection limit was 0.01 ng mL-1 . The sensor exhibited high sensitivity and specificity, as demonstrated by testing structurally similar organic compounds such as salbutamol, clenbuterol and dopamine. The practicality of the developed colorimetric immunosensor was supported by the successful detection of RAC in pork samples with recovery ranging from 94.00% to 106.00%. CONCLUSION: We designed a novel sandwich-type noncompetitive colorimetric immunoassay for the detection of trace levels of RAC in pork. The proposed method can also be used for the detection of toxins in food products via PtNPs-PV amplification.