基于表面钝化效应的增强型均相阴极光电化学分析  

Enhanced and Homogeneous Cathodic Photoelectrochemical Analysis Based on Surface Passivation Effect

作　　者：闫梦华 杨高霞 王光丽 YAN Meng-Hua;YANG Gao-Xia;WANG Guang-Li(Key Laboratory of Synthetic and Biological Colloids,Ministry qf Education,School of Chemical and Material Engineering,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学化学与材料工程学院,合成与生物胶体教育部重点实验室,无锡24122

出　　处：《分析化学》2023年第2期276-286,共11页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.22174054)资助。

摘　　要：基于Cd^(2+)对硒化铅量子点(PbSeQDs)光电流的增强作用,构建了新型的分离式均相光电化学(PEC)传感器,分别用于miRNA-21和癌胚抗原(CEA)的灵敏检测。此传感器利用含有T-Hg^(2+)-T碱基错配的发夹结构DNA,其环部分别与miRNA-21或CEA适配体的互补链结合形成双链,借助DNA链置换反应进行信号放大,释放发夹结构中的Hg^(2+)。Hg^(2+)与CdSQDs进行阳离子交换释放Cd^(2+),Cd^(2+)与固定在电极上的PbSeQDs发生阳离子交换反应,在PbSeQDs表面形成硒化镉(CdSe),消除了Pb Se表面的电子-空穴复合中心,提高了电荷的分离效率,增强了光电流响应。本方法检测miRNA-21的线性范围为5.0×10^(-16)~5.0×10^(-10)mol/L,检出限为6.8×10^(-17)mol/L(S/N=3);对CEA检测的线性范围为5.0×10^(-2)~5.0×10^(4)pg/mL,检出限为0.007 pg/mL(S/N=3)。此传感器具有良好的抗干扰性和选择性,可用于实际样品的检测。Homogeneous and split-type photoelectrochemical (PEC) sensors based on the enhancement effect of Cd^(2+)on the photocurrent of lead selenide quantum dots (Pb Se QDs) were constructed for sensitive detection of miRNA-21 and carcinoembryonic antigen (CEA).The detection method used the hairpin DNA assembly by T-Hg^(2+)-T base mismatch,whose loops were combined with miRNA-21 or the complementary strand of CEA aptamer to form double strands.Signal amplification was carried out by non-enzymatic DNA strand displacement reaction to release Hg^(2+)in the hairpin structure,and then the released Hg^(2+)exchanged ions with cadmium sulfide quantum dots (Cd S QDs) to release Cd^(2+).Then,Cd^(2+)reacted with Pb Se QDs modified electrode to form cadmium selenide (Cd Se) layer on its surface,which eliminated the electron-hole recombination center on the surface and improved the charge separation efficiency,realizing enhanced photocurrent output.The experimental results showed that the linear range for detection of miRNA-21 was 5.0×10^(-16)–5.0×10^(-10)mol/L,and the detection limit was 6.8×10^(-17)mol/L (S/N=3).The logarithm of the concentration of CEA was linear with the photocurrent in the range of 5.0×10^(-2)–5.0×10^(4)pg/mL,and the detection limit was 0.007 pg/mL (S/N=3).The developed PEC biosensors showed good selectivity and could be used for detection of real samples with satisfactory results.

关 键 词：阴极光电化学分析 硒化铅量子点 无酶链置换放大反应 表面钝化 

分 类 号：O657.1[理学—分析化学] TP212.3[理学—化学]