Electrodeposition of silver–DNA hybrid nanoparticles for electrochemical sensing of hydrogen peroxide and glucose

Silver–DNA hybrid nanoparticles with controlled dimension were electrodeposited on a glassy carbon electrode by the reduction of silver in the aid of DNA. The hybrid nanoparticles showed a narrow size distribution and a favorable catalytic ability to reduction of hydrogen peroxide and dissolved oxygen, which were related to the DNA concentration in deposition solution and the deposition time. The presence of DNA avoided the further aggregation of silver nanoparticles and improved the catalytic ability of the nanoparticles. The modified electrode obtained showed a linear response to hydrogen peroxide concentration ranging from 2.0 μM to 2.5 mM with a limit of detection of 0.6 μM and a sensitivity of 773 μA mM−1 cm−2. Based on the dissolved oxygen consumption during the oxidation process of glucose catalyzed by the immobilized glucose oxidase, a glucose biosensor with a limit of detection of 9.0 μM and a linear range from 50 μM to 1.2 mM was fabricated. The biosensor excluded the interference from ascorbic acid, acetaminophen, and uric acid that always coexist with glucose in samples.