基于电化学发光和阻抗技术研究DNA单碱基错配

Study on the single-base mismatch DNA by electrochemiluminescence and impedance biosensor

单碱基错配的识别和稳定性差异在核酸多态性研究中至关重要。在同一电化学传感器平台上,采用电化学发光(ECL)和电化学阻抗(EIS)2种技术,协同研究DNA链中不同类型和不同位点的单碱基错配识别和稳定性差异。电极表面具有茎环构象的探针DNA与完全互补DNA、不同类型或不同位点单碱基错配DNA杂交前后的ECL和EIS信号强度变化有显著差异。信号强度变化可揭示单碱基错配识别的稳定性。结果表明,DNA链中心位点的C-A单碱基错配稳定性低于链两端的,靠近键合电极表面双链链端的C-A单碱基错配稳定性低于非键合电极表面双链链端的,同一中心位点C-X碱基对的稳定性顺序为C-G≫C-T>C-A≥C-C。研究结果可为核酸多态性研究提供参考。

Single-base mismatch is very important in the study of nucleic acid polymorphism.The discrimination and the stability differences of single-base mismatches of different types or on different sites were studied on the same electrochemical biosensor by electrochemiluminescence(ECL)and electrochemical impedance spectroscopy(EIS)simultaneously in this paper.Significant changes of ECL and EIS signals could be detected before and after hybridizations of probe DNA being stem-loop conformation on the electrode surface with completely complementary DNA and single-base mismatch DNA of different types or on different sites.The variation of these signal changes revealed the stability of single-base mismatch.The results showed that the stability of C-A single-base mismatch at the center position of DNA chain was lower than that at both ends of the chain,and the stability of C-A single-base mismatch near the terminal of double strand DNA bonding to the electrode surface was lower than that at the terminal of double strand DNA not bonding to the electrode surface.The stability order of C-X base pair at the same center was ranked as C-G≫C-T>C-A≥C-C.The results of this study provide a reference for the study of nucleic acid polymorphism.