An impedance array biosensor for detection of multiple antibody-antigen interactions

• Published in: Analyst (London) Vol. 131; no. 6; p. 745
• Main Authors: Yu, Xiaobo, Lv, Renji, Ma, Zhenqiu, Liu, Zhihong, Hao, Yanhong, Li, Qingzhang, Xu, Danke
• Format: Journal Article
• Language: English
• Published: England 01.01.2006
• Subjects: Animals; Antigen-Antibody Reactions; Biosensing Techniques; Electric Impedance; Electrochemistry - instrumentation; Electrochemistry - methods; Electrodes; Gold; Hepatitis B e Antigens - immunology; Hepatitis B Surface Antigens - immunology; Immunoglobulin G - immunology; Rats
• ISSN: 0003-2654
• DOI: 10.1039/b517148b

Electrochemical impedance spectroscopy (EIS) combined with a gold electrode array was developed to detect multiple antibody-antigen interactions. Hepatitis B surface antigen (HBsAg), as a model sample, was employed to evaluate the characteristics of the biosensor. The array was fabricated by immobilizing antibodies on the self-assembled molecules surface of the electrodes. The surface characteristics of the array during the binding process including the antibody-antigen conjugation and the sandwich complex with HRP-labeled antibody, as well as the precipitation layer, were characterized by atomic force microscopy (AFM) and electrochemical impedance spectroscopy, respectively. A linear relationship between electron-transfer resistance and the concentrations of HBsAg ranged from 10 pg ml(-1) to 1 ng ml(-1) and the detection limit of 10 pg ml(-1) was obtained. 100 pg ml(-1) antigen samples, such as rat IgG, HBsAg and HBeAg, as well as the antigen mixture, were incubated with the relative antibody-modified electrodes on the array. No obvious cross-talk reaction was observed. All these results confirm the feasibility of applying electrochemical impedance spectroscopy to the electrode array.