An Host-Guest Electrochemical Sensor for DNA Ligase Detection

We herein constructed a electrochemial sensor for T4 DNA ligase detction. In the sensor, the hairpin dsDNA terminal-labeled with 4-((4-(dimethylamino)phenyl)azo)benzoic acid (dabcyl) and thiol group was immobilized on Au electrode surface as the probe by Au-S bond, and the CdS nanoparticles surface-modified with β-cyclodextrins (ZnS-CD) were employed as electrochemical signal provider and host-guest recognition element. After T4 DNA ligase repairing single-strand breaks in duplex DNA, the dsDNA probe underwent a significant conformational change, which forced dabcyl away from the electrode. As a result, formerly shielded dabcyl became accessible to host-guest recognition between β-cyclodextrin and dabcyl, thus the target repairing event could be sensitively transduced to electrochemical signal provided by ZnS-CD.