中文摘要：

采用自组装法将带巯基的捕获DNA探针固定到金电极表面，利用杂交反应将可卡因适体固定到电极上制得可卡因适体传感器．以钌联吡啶为电活性指示剂，检测适体与目标分析物——可卡因特异性结合后，电化学活性物质钌联吡啶的电信号的降低，实现对可卡因的定量检测．考察了缓冲液的pH，扫描速度，DNA探针及适体固定时间等条件对传感器测定可卡因信号响应的影响．结果表明在pH7．4时该传感器检测的范围为2×10^-4～1．0×10^-3mol／L，检测下限为6×10^-5mol／L．该传感器稳定性好，抗干扰能力强．

英文摘要：

In this paper, capture DNA probe with mercapto - group was immobilized on a surface of gold electrode via self - assembly. Then, cocaine aptamer biosensor was constructed by immobilization of cocaine aptamer on the electrode through hybridization. Using tris （2.2＇ - bippridyl） diehlororuthenium （ Ⅱ ） hexahydrate as electroactive indicator, the quantitative determination of cocaine was carried out, based on the decrease of electrical signal of tris （2.2＇ - bippridyl） dichlororuthenium （ Ⅱ ） hexahydrate after the combination of aptamer with target cocaine. The effects of scan rates pH, the immobilizing time of capture probe and aptamer on the signal were investigated. The results showed that the biosensor exhibits linear response to cocaine in the range of 2 ×10^-4--1. 0×10^-3 mol/L with a detection limit of 6×10^-5 mol/L. The biosensor has some advantages, such as high stability and specificity. This sensor has been used to determine cocaine in a real serum sample.