Amplified Electrochemical Immunoassay of E-coli in Dairy Product Using Functionalized ZnONRs
  
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DOI:10.3969/j.issn.1004-4957.年份.月份
KeyWord:nanocomposite-based labels  amplified electrochemical immunoassay  dairy product  E-coli
  
AuthorInstitution
ZHANG Xin-ai*,JIANG Yu-xiang,SHEN Jian-zhong,HAN En,DONG Xiao-ya 江苏大学食品与生物工程学院
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Abstract:
      In this paper,an amplified electrochemical immunoassay using nanocomposite based labels({dAb-ZnO-FCA}) was developed for the assay of E-coli as indicator bacteria relevant to the quality of dairy product.The {dAb-ZnO-FCA} labels were designed by exploiting nanocomposite(ZnO@SiO2) as the carriers for immobilization of detection antibody(dAb) and ferrocenecarboxylic acid(FCA),in which dAb was used for recognition of E-coli and FCA tags served as signal-generating molecule.Greatly amplified signal was achieved in the sandwich-type immunoassay when enormous FCA linked to ZnO@SiO2.Under the optimal experimental conditions,a linear relationship between peak current of FCA and logarithmic value of E-coli concentration was obtained in the range of 2.0×102-2.0×106 cfu/mL with a detection limit(S/N=3) of 100 cfu/mL.The proposed method was used to determine E-coli in dairy product,and the recoveries of standard additions were in the range of 95.8%-105%.The results indicated that the electrochemical immunoassay gave a useful approach for E-coli analysis with rapid response,high sensitivity and specificity,and thus provided a powerful tool for estimating the quality of dairy product.
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