摘要
构建了一个以亚甲基蓝(MB)为杂交指示剂的电化学DNA传感体系:通过自组装的方式将巯基改性的单链DNA5′端(HS-ssDNA)连接到金电极表面形成Au-ssDNA,当检测体系中加入和Au-ssDNA互补的目标单链DNA(cssDNA)时,会形成一个双链DNA系统(Au-dsDNA),加入MB并通过循环伏安法检测了杂交过程中的信号变化,验证了Au-ssDNA及Au-dsDNA的形成。在4.0×10-6～1.0×10-5mol/L内,检测灵敏度随MB浓度的增加而升高,当浓度达到2.0×10-5mol/L时接近最大值。示差脉冲伏安法检测结果表明,该检测体系对目标DNA的选择性识别能力高,可区分具有单碱基错配的目标DNA序列。检测体系对目标DNA的检测灵敏度随着目标DNA浓度的增加而增加,在5.0×10-10～1.8×10-9mol/L内呈线性关系,计算所得对目标DNA的检测限为5.0×10-10mol/L。使用寿命检测表明,经过5次变性/杂交循环后,检测信号降低并接近于检测限。
An electrochemical DNA sensing system was constructed and investigated with methylene blue（MB） as hybridization indicator. 5＇-End-SH modified DNA （HS-ssDNA） probes were firstly self- assembled onto the Au-electrode surface, and then hybridized with the complementary single stranded DNA（cssDNA） to form double-stranded DNA system （Au-dsDNA）. The results based on differential pulse voltammetry （DPV） showed that cathodic signals of current system were＇ affected by methylene blue （MB） concentration. Furthermore, a thin film formed on Au electrode surface was successfully identified via DPV measurement. Sensitivity of sensing probe was enhanced when the MB concentration ranged from 4.0 ×10×^-6 to 1.0×10^-5 mol/L. Recognizability 5 mol/L, and the optimum concentration of MB was suggested to be of a single strand DNA with one mismatch indicated a sensing system with high specificity was achieved. The sensitivity was concentration ranged from 5.0×10^-10 mol/L to 1.8×10^-9 estimated to be ca 5.0×10^ -10 mol/L. Moreover, recycling life times. linear and increased when the target DNA concentration ranged from 5.0×10^-10 mol/L to 1.8×10^-9mol/L, and the detecting limitation was of the sensing probe was detected to be 5 times.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2008年第12期1183-1186,1197,共5页
Fine Chemicals
基金
天津市自然科学基金项目(07JCYBJC15900)~~
关键词
电化学DNA生物传感器
杂交
亚甲基蓝
金电极
生物工程
electrochemical DNA biosensor
hybridization
methylene blue
Au-electrode
biological engineering
