Label-free immunosensor based on one-step electrodeposition of chitosan-gold nanoparticles biocompatible film on Au microelectrode for determination of aflatoxin \B1\ in maize
By Haihua Ma and Jizhou Sun and Yuan Zhang and Chao Bian and Shanhong Xia and Tong Zhen
Published in Biosensors and Bioelectronics
2016
Abstract
Gold nanoparticles (AuNPs) embedded in chitosan (CHI) film, well-dispersed and smaller in size (about 10 nm), were fabricated by one-step electrodeposion on Au microelectrode in solution containing chitosan and chloride trihydrate. The nano-structure CHI-AuNPs composite film offers abundant amine groups, good conductivity, excellent biocompatibility and stability for antibody immobilization. The combination of aflatoxin \B1\ (AFB1) with immobilized antibody introduces a barrier to electron transfer, resulting in current decreasement. The morphologies and characterizations of modified microelectrodes were investigated by scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FT-IR). The proposed non-enzyme and label-free immunosensor exhibited high sensitive amperometric response to \AFB1\ concentration in two linear ranges of 0.1 to 1 ng mL?1 and 1 to 30 ng mL?1, with the detection limit of 0.06 ng mL?1 (S/N=3). The immunoassay was also applied for analysis of maize samples spiked with AFB1. Considering the sample extraction procedure, the linear range and limit of detection were assessed to be 1.6