多重金属离子检测用三维石墨烯电化学生物传感器敏感膜的构筑

摘要

采用氧化还原法制备出三维石墨烯，在对其氨基功能化的基础上，利用静电吸附作用，将单链 DNA 固定在氨基化三维石墨烯（G －NH2）表面，通过与重金属离子（Ag ＋，Hg2＋，Cu2＋）配合形成双链 DNA．采用 TEM和 SEM对三维石墨烯进行表征，同时利用 AFM和 XPS 对 G －NH2固定 DNA 前后的表面形貌和化学元素组成进行测试．结果表明氨基化三维石墨烯表面比较平整光滑，XPS 的信号峰发生变化证明了 DNA 已成功地固定到 G －NH2上．采用电化学交流阻抗法（EIS）对 DNA 固定和重金属离子检测前后三维石墨烯自组装膜的电化学性能变化进行分析．结果表明，DNA 固定后及重金属离子检测前后，膜的界面电荷转移电阻值均发生明显变化．本文制备的三维石墨烯材料可用作电化学生物传感器敏感膜以吸附生物分子，并可同时进行多种重金属离子的检测．%The 3D graphene was prepared by redox mothod and then was functionalized by amino-modified (G-NH2 ).The single-stranded DNA could immobilize onto the surface of the fabricated biosensor via the elec-tro-static interaction between DNA and G-NH2 and coordination with the relative heavy metal ions (Ag +, Hg2 +,Cu2 +).The surface morphology was determined using transmission electron microscopy (TEM)and scanning electron microscopy (SEM).Atom force microscopy (AFM)and X-ray photoelectrons spectroscopy (XPS)were applied to measure the chemical structure and componenets of the fabricated G-NH2 before and after being immobilized DNA.The results showed that the surface of 3D G-NH2 was smooth.Signal changes of XPS peak demonstrated that DNA were immobilize onto the surface of 3D G-NH2 .The electrochemical imped-ance spectrum was used to characterize the electrochemical perforamance of the biosensor during the procedure of the detection of heavy metal ions.It explored that the Rct values were changed significantly after DNA was immoloilized onto the surface of 3D G-NH2 and then coordinated with the relative heavy metal ions.This study demonstrated this kind of biosensor could be used to adsorb biomolecules and detect the co-exist system of many heavy metal ions.