A novel DNA sensor was designed for the determination of breast cancer genes based on three electrochemical probes,the negative electrochemical probe [Fe(CN)6] 3-/4-,methylene blue and the positive electrochemical probe [Ru (NH3) 6] 3 + The breast cancer genes DNA sensor was fabricated by immobilizing a breast cancer gene ssDNA onto the surface of gold nanoparticles-multiwalled carbon nanotubes(MWCNT)-Nafion modified gold electrode through adsorption,and characterized by cyclic voltammetry,differential pulse voltammetry and electrochemical impedance method.Under the optimized conditions,in 5 mmol/L K3 [Fe (CN) 6]--5 mmol/L K4 [Fe (CN) 6] (pH =7.4) solution,the electrochemical current response of the sensor was linear with the logarithm of the breast cancer gene concentration in range of 0.1-500.0 nmol/L,with a detection limit(S/N =3) of 0.03 nmoL/L.While using methylene blue as the electrochemical probe,the electrochemical current response was linear with concentration of breast cancer gene in range of 1.0-500.0 nmol/L,and the detection limit was 0.3 nmol/L.Based on the different binding ability of [Ru (NH3) 6] 3 + with ssDNA and dsDNA,the current response of the sensor using [Ru (NH3)6]3+ as the probe was still linear with concentration of breast cancer gene in the range of 1.0-500.0 nmol/L.The detection limit was 0.3 nmol/L.Among three kinds of electrochemical probes,[Fe(CN)6] 3-/4-probe had the lowest detection limit and the widest linear range for the detection of breast cancer gene.%构建了以3种不同电活性物质(铁氰化钾平衡电对、亚甲基蓝和六氨合钌)为电化学信号探针,检测乳腺癌基因片段(乳腺癌DNA)的电化学传感器.利用吸附作用将探针ssDNA固定于金纳米-多壁碳纳米管-Nafion复合纳米材料修饰金电极表面,制备了DNA电化学传感器.采用循环伏安法、电化学阻抗法和微分脉冲伏安法,对DNA电化学传感器进行表征和定量分析.实验结果表明,在5 mmol/L K3[Fe(CN)6]-5mmol/L K4[Fe(CN)6]平衡电对电化学探针检测液中,乳腺癌DNA的线性范围为0.1～500.0 nmol/L,其检出限(S/N=3)为0.03 nmol/L.以20 μmol/L亚甲基蓝为电化学探针检测液时,乳腺癌DNA的线性范围为1.0 ～ 500.0 nmol/L,检出限为0.3 nmol/L.利用50 μmol/L六氨合钌电化学探针检测时,乳腺癌DNA的线性范围为1.0 ～ 500.0 nmol/L,检出限为0.3 nmol/L.3种电化学探针中,利用铁氰化钾平衡电对探针检测乳腺癌DNA的检出限最低,线性范围最宽.该传感器可用于其他DNA的检测分析.
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