基于聚乙烯亚胺功能化石墨烯的高灵敏电化学阻抗传感方法用于血清中mircoRNA-155检测

建立血清中癌症标志物microRNA-155的高灵敏电化学检测方法.采用一步法制备了聚乙烯亚胺功能化的石墨烯,通过静电相互作用制备了金纳米粒子功能化的石墨烯复合物.将该复合物用作电极基底材料,基于金纳米粒子与DNA捕获探针上的SH基团之间形成的强烈的S-Au键可将DNA捕获探针固定到电极表面.通过DNA捕获探针对microRNA-155的特异性识别作用可特异性地捕获待测样品中的microRNA-155分子.利用生物分子对电极表面电子传递的阻碍作用,从而实现对microRNA-155分子的电化学阻抗传感器的构建.在最优条件下,该传感器的阻抗值与microRNA-155的浓度的对数值在1~1000 nmol/L浓度范围内呈现良好的线性关系,检出限为0.51 nmol/L(S/N=3),可实现实际血清样品中的microRNA-155的灵敏快速检测.

Electrochemical Impedance Sensing for Sensitive Detection of MircoRNA-155 in Serum Based on Polyethyleneimine Functionalized Graphene

The paper is going to establish a highly sensitive electrochemical method to determine microRNA-155,a tumor marker in serum.Polyethyleneimine functionalized graphene(PEI-G)is prepared through a one-pot synthesis method and then AuNPs/PEI-G composite is prepared through electrostatic interaction between PEI-G and AuNPs.Then the AuNPs/PEI-G composite is used as the substrate of electrode to immobilize the DNA capture probe through the strong S-Au between AuNPs and SH of DNA capture probe.Due to the special recognition of DNA capture probe to microRNA-155,microRNA-155 can be captured onto the surface of electrode and the electrochemical impedance sensor can be constructed through the measurement of impedance value after the capture.At the optimized experimental condition,the impedance value and logarithm of concentration of microRNA-155 show a fine linear relationship within the range of 1~1000 nmol/L with a detection limit of 0.51 nM(S/N=3)and can be used for the quick detection of microRNA-155 in the real sample of serum.