Cheng Alan K H, Ge Bixia, Yu Hua-Zhong
Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Anal Chem. 2007 Jul 15;79(14):5158-64. doi: 10.1021/ac062214q. Epub 2007 Jun 13.
This paper reports a simple electrochemical approach for the detection of the ubiquitous protein lysozyme using aptamer-modified electrodes. Anti-lysozyme DNA aptamers were immobilized on gold surfaces by means of self-assembly, for which the surface density of aptamers was determined by cyclic voltammetric (CV) studies of redox cations (e.g., [Ru(NH3)6]3+) bound to the surface via electrostatic interaction with the DNA phosphate backbone. Upon incubation of the electrode with a solution containing lysozyme, the CV response of surface-bound [Ru(NH3)6]3+ changed substantially, and the relative decrease in the integrated charge of the reduction peak can be tabulated as a quantitative measure of the protein concentration. It is significant that the on-chip protein/aptamer binding constant and the optimized surface density to achieve the best detection limit can be evaluated. This biosensor is label-free and offers an alternative, sensitive, and versatile method for protein detection, which is beneficial to the ever-growing interests of fabricating portable bioanalytical devices with simple electrical readout protocols.
本文报道了一种使用适配体修饰电极检测普遍存在的蛋白质溶菌酶的简单电化学方法。抗溶菌酶DNA适配体通过自组装固定在金表面，通过对与DNA磷酸骨架静电相互作用结合到表面的氧化还原阳离子（如[Ru(NH₃)₆]³⁺）进行循环伏安（CV）研究来确定适配体的表面密度。将电极与含有溶菌酶的溶液孵育后，表面结合的[Ru(NH₃)₆]³⁺的CV响应发生显著变化，还原峰积分电荷的相对降低可列表作为蛋白质浓度的定量测量。重要的是，可以评估芯片上蛋白质/适配体的结合常数以及实现最佳检测限的优化表面密度。这种生物传感器无需标记，为蛋白质检测提供了一种替代、灵敏且通用的方法，这有利于人们对制造具有简单电学读出协议的便携式生物分析设备日益增长的兴趣。
