Single-stranded DNA-based Immobilization of Ag Nanoparticles for Enzymeless H_2O_2 Detection

摘要

In this communication, we report a new method for effective immobilization of Ag nanoparticles (AgNPs) on thiolated single-stranded DNA (thiol-ssDNA) modified Au electrode (AuE) surface via coordination interactions between the nitrogen atoms of DNA bases and AgNPs. It suggests that the AgNP-immobilized AuE exhibits notable Catalytic performance for H_2O_2 reduction and the loading of AgNPs on the AuE surface and therefore the effective catalytic area can be tuned by the immobilization time of thiol-ssDNA and adsorption time of AgNPs. This H_2O_2 sensor has a fast amperometric response time of less than 3 s and its linear range and detection limit are estimated to be from 0.1 mM to 160 mM (r = 0.995) and 0.8 μM at a signal-to-noise ratio of 3, respectively.