Direct electrochemistry of myoglobin at silver nanoparticles/myoglobin biocomposite: Application for hydrogen peroxide sensing

Herein we report a novel hydrogen peroxide (H2O2) sensor based on direct electrochemistry of myoglobin at a silver nanoparticles/myoglobin (Ag-NPs/MB) biocomposite modified electrode. The green synthesized Ag-NPs and MB were used for the fabrication of Ag-NPs/MB biocomposite. The fabricated Ag-NPs and Ag-NPs/MB biocompo site were characterized by using TEM and SEM respectively. A good direct electron transfer of MB is realized at Ag-NPs/MB biocomposite electrode rather than direct drop casting of MB onto Ag-NPs modified electrode, which indicates that the native structure of MB is retained in the biocomposite modified electrode. The apparent heterogenous electron transfer rate constant (k(s)) is calculated as 3.02 s(-1), which confirms a fast direct electron transfer of MB at the biocomposite electrode. A fast amperometric response for H2O2 (<5 s) at Ag-NPs/MB biocomposite modified electrode indicates a good catalytic activity of the modified electrode. The H2O2 detection is found in the linear response range from 1 mu M to 3 mM with the detection limit of 0.088 mu M. The sensitivity is calculated as 0.357 mu A mu M-1 cm(-2). In addition, the fabricated biosensor shows a good consistency along with excellent precision. (C) 2014 Elsevier B.V. All rights reserved.