Electrochemical detection at low temperature for a specific nucleobase of target nucleic acids by an abasic site-containing DNA binding ligand

Single-nucleotide polymorphism analysis based on fabrication of the abasic site (AP site) in the thiolated DNA duplexes is demonstrated. The AP site allows an electrochemical indicator to bind to target nucleotides accompanied by electrochemical signaling and to detect a specific nucleobase of a target nucleic acid. A mixed self-assembled monolayer of thiolated AP site-containing probe DNA is hybridized with the target DNA so as to direct the AP site toward the target nucleobase. In this way, hydrophobic microenvironments are provided for the electrochemical indicator to recognize the specific nucleobase on the DNA duplex based on the difference in the electrochemical response. The electrochemical response is found to be strengthened at low temperature. The enhanced electrochemical response of riboflavin induced by temperature in an AP site-containing DNA duplex is used to detect thymidine specifically based on an electrochemical approach.