Electroactive bacteria as whole-cell biosensor for sensitive detection of hydrogen peroxide

Hydrogen peroxide (H2O2) is a widely used strong oxidizer and has harmful effects on human health with excessive exposure. Herein, we proposed a simple and effective method for H2O2 detection by utilizing elec-troactive bacteria (EAB) as a whole-cell biosensor. The proposed method was achieved by utilizing the multi-heme c-type cytochromes (central components of microbial extracellular electron transfer) of model EAB Shewanella oneidensis MR-1 to catalyze the oxidation of tetramethylbenzidine in the presence of H2O2. Owing to the excellent peroxidase-like activity of the multiheme c-cyts, this H2O2 detection method has a wide dynamic range between 0.1 and 1000 mu M and a low detection limit of 0.17 mu M. The proposed method, when coupled with glucose oxidase, displayed a high sensitivity (0.57 mu M) and broad linear range (1 mu M -10 mM) for glucose. Moreover, this method has high specificity and good recovery for detecting H2O2-spiked real samples. Overall, this study has developed a novel biosensing platform that provides an alternative approach to H2O2 detection.