A sensitive enzymeless sensor for hydrogen peroxide based on the polynucleotide-templated silver nanoclusters/graphene modified electrode.

A novel, sensitive and enzymeless electrochemical sensor based on polynucleotide-templated silver nanoclusters (DNA-AgNCs)/graphene composite film was developed for the detection of hydrogen peroxide. The graphene modified glassy carbon electrode (GCE) was employed because graphene has several advantages including excellent conductivity, biocompatibility, and large surface area to volume ratio. In addition, it was found that DNA-AgNCs have remarkable electrocatalytic activity toward the reduction of hydrogen peroxide, and can be easily immobilized onto the surface of the graphene/GCE by π-π stacking. The sensor based on the (DNA-AgNCs)/graphene/GCE exhibited a rapid response (ca. 3s), a low detection limit (3 μM), a wide linear range from 15 μM to 23 mM, high selectivity, as well as good repeatability. Moreover, the common interfering species, such as ascorbic acid, uric acid, dopamine, glutathione, and l-cysteine, did not result in any interference. This present work may expand the use of silver nanoclusters in the field of electrochemical sensor.