普鲁士蓝@石墨烯-壳聚糖纳米复合物用于构建microRNA电化学传感器的研究

制备了基于普鲁士蓝(PB)、石墨烯(GN)、壳聚糖(Chi)的纳米复合物(PB@GN-Chi),并将其修饰在玻碳电极表面制得microRNA电化学传感器。实验发现,GN可有效提高敏感膜的导电性能和比表面积,增强PB在电极表面的稳定性和传感器的重现性。通过戊二醛的交联作用,将氨基化的捕获探针(ssDNA)固载在PB@GN-Chi修饰的电极表面,并用于miR-21的检测。以透射电子显微镜对纳米复合物的形态进行表征,采用循环伏安法、示差脉冲伏安法对传感器的电化学特性进行研究。实验结果表明,该传感器具有良好的稳定性和重现性,在2.8~2.8×10~4pmol/L浓度范围内,响应电流与miR-21浓度的对数呈线性关系,检出限为0.87 pmol/L,可用于miR-21的检测。

Development of microRNA Electrochemical Biosensor Based on Prussian Blue@Graphene-Chitosan Nanocomposite Prepared by in situ Deposition

A microRNA(miR,miRNA) electrochemical biosensor was proposed in the present research.Firstly,graphene(GN) was dispersed in the chitosan(Chi) solution to promote the conductivity of chitosan film.Then,prussian blue (PB) was in situ deposited on GN to obtain the PB@GN-Chi nanocomposite.The obtained nanocomposites were modified on the surface of electrode.Compared with the PB@GN-Chi prepared by ultrasonic method,the prepared composite could effectively prevent PB leaking into detection solution and display a prominent stability when modified on the electrode.The capture probe was subsequently modified by amino group and covalently linked to the modified electrode via glutaraldehyde.After blocked by hexanethiol,the miRNA biosensor was successfully prepared.The prepared PB@GN-Chi nanocomposite was observed with transmission electron microscope,and the electrochemical characteristics of the miRNA biosensor were investigated by cyclic voltammetry and differential pulse voltammetry.Under the optimal conditions,the biosensor displayed a linear relationship between current response and the logarithm of concentration of miR-21 in the range of 2.8-2.8 × 104 pmol/L.The detection limit was calculated to be 0.87 pmoL/L.The prepared biosensor owns good stability and repeatability,and could be employed to detect miR-21 in human serum sample.