基于β-环糊精主客体识别作用的均相DNA杂交电化学生物分子识别研究

摘要

基于β-环糊精(β-CD)和间甲基苯甲酸(mTA)的主客体识别,建立了均相DNA杂交电化学生物传感技术.将主体分子β-CD通过电化学聚合的方法固定在氮乙酰基苯胺修饰的玻碳电极表面,同时将mTA通过酸胺缩合反应标记在探针DNA序列上,与目标DNA在溶液均相中杂交之后,用修饰好的电极对探针DNA上的mTA进行主客体识别.以两种嵌入剂作为电化学指示剂——亚甲基蓝(MB)和道诺霉素(DNM),证实了方法的可行性.MB的电化学信号与完全互补DNA浓度在2.0× 10-12～2.0× 10-10 mol/L之间呈良好线性关系,检出限为7.6×10-13 mol/L;DNM的电化学响应与完全互补DNA浓度在1.0× 10-12 ～1.0× 10-9 mol/L之间呈良好线性关系,检出限可达6.0×10-13 mol/L,并表现出良好的重现性和稳定性.%A sensitive electrochemical DNA biosensing through homogenous hybridization was fabricated based on host-guest recognition system due to the very strong inclusion between β-cyclodextrin (β-CD) and m-toluic acid (mTA).fβ-CD,as the host molecule,was electropolymerized on the poly (N-acetylaniline)-modified glassy carbon electrode,and mTA,as the guest,was labeled on the probe DNA using acid and amine condensation reaction.Using the host-guest recognition,the single probe DNA and hybrid double-stranded DNA were connected to the electrode surface.Two intercalators were used as electrochemical indicators to detect DNA hybridization,methylene blue (MB) and daunorubicin (DNM).The electrochemical signals of MB were linear with the concentrations of complementary DNA from 2.0× 10-12 mol/L to 2.0× 10-10 mol/L with a detection limit of 7.6× 10-13 mol/L.The electrochemical responses of DNM were linear with the concentrations of complementary from 1×10-12 mol/L to 1 ×10-9 mol/L with a detection limit of 6.0×10-13 mol/L.This DNA biosensing technology exhibited excellent reproducibility and stability.