Glucose oxidase as a blocking agent-based signal amplification strategy for the fabrication of label-free amperometric immunosensors  

作　　者：SONG ZhongJu YUAN Ruo CHAI YaQin CHE Xin LV Ping 

机构地区：[1]Key Laboratory on Luminescence and Real-Time Analysis,Ministry of Education,College of Chemistry and Chemical Engineering,Key Laboratory of Eco-environments in Three Gorges Reservoir Region,Southwest University,Chongqing 400715,China

出　　处：《Science China Chemistry》2011年第3期536-544,共9页中国科学（化学英文版）

基　　金：financially supported by the National Natural Science Foundation of China(20675064);the Ministry of Education of China(708073);the Natural Science Foundation of Chongqing City (CSTC-2009BA1003);High Technology Project Foundation of Southwest University(XSGX 02)

摘　　要：An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalized chitosan,which possessed not only efficient redox-activity but also excellent film-forming ability,was coated on the bare glass carbon electrode. Moreover,the thiol groups(SH)in the ferrocenyl compound were used for gold nanoparticles immobilization via the strong bonding interaction,which could further be utilized for the immobilization of antibody biomolecules with well-retained bioactivities.Finally,glucose oxidase(GOD)as the enzyme membrane was employed to block the possible remaining active sites and avoid the nonspecific adsorption.With the excellent electrocatalytic properties of GOD towards glucose,the amplification of antigen-antibody interaction and the enhanced sensitivity could be achieved.Under the optimal conditions,the linear range of the proposed immunosensor for the determination of carcinoembryonic antigen(CEA)was from 0.05 to 100 ng/mL with a detection limit of 0.02 ng/mL(S/N=3).Moreover,the immunosensor exhibited good selectivity,stability and reproducibility, which provided a promising potential for clinical immunoassay.An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalized chitosan,which possessed not only efficient redox-activity but also excellent film-forming ability,was coated on the bare glass carbon electrode. Moreover,the thiol groups（SH）in the ferrocenyl compound were used for gold nanoparticles immobilization via the strong bonding interaction,which could further be utilized for the immobilization of antibody biomolecules with well-retained bioactivities.Finally,glucose oxidase（GOD）as the enzyme membrane was employed to block the possible remaining active sites and avoid the nonspecific adsorption.With the excellent electrocatalytic properties of GOD towards glucose,the amplification of antigen-antibody interaction and the enhanced sensitivity could be achieved.Under the optimal conditions,the linear range of the proposed immunosensor for the determination of carcinoembryonic antigen（CEA）was from 0.05 to 100 ng/mL with a detection limit of 0.02 ng/mL（S/N=3）.Moreover,the immunosensor exhibited good selectivity,stability and reproducibility, which provided a promising potential for clinical immunoassay.

关 键 词：amperometric immunosensor CHITOSAN gold colloidal nanoparticles（GNPs） Ferrocene-monocarboxylic（Fc-COOH） carcinoembryonic antigen（CEA） 

分 类 号：O441[理学—电磁学] Q554[理学—物理]