基于适体竞争机理的溶菌酶电化学传感器

A lysozyme electrochemical sensor based on aptamer competition

制备了基于溶菌酶适体竞争机理的信号减弱型电化学传感器,在玻碳电极上修饰羧基化的多壁碳纳米管,将带有氨基的互补适体DNA连接到多壁碳纳米管上。由于道诺霉素崁入电极上的互补DNA,而产生电化学信号,当有目标物时,适体与结合力更高的溶菌酶结合,原本的互补链解链,导致插入双链的道诺霉素脱落,电化学信号减弱。以微分脉冲伏安法测定溶菌酶,响应的范围为1～500 nmol/L,相关系数0.999,检测下限为0.5 nmol/L(S/N=3)。

A simple signal-off electrochemical lysozyme aptamer sensor based on the mechanism of competition was described. After the multiwalled carbon nanotubes （MWCNT） were modified on the surface of a glassy carbon electrode, aptamer dsDNA was assembled through NH2-COOH on MWCNT surfaces. In the presence of the indicator daunomycin, an electrical signal can be observed due to the insertion of daunomycin into dsDNA. The electrical chemical signal decreased when lysozyme was added because the competition between daunomycin and lysozyme resulted in the drop of daunomycin from dsDNA. Under the optimum conditions, the biosensor exhibited a linear range from 1 nmol/L to 500 nmol/L for lysozyme, with a correlation coefficient of 0. 999. The detection limit （3σ） was 0. 5 nmoL/L.