Molybdenum sulfide/nitrogen-doped carbon nanowire-based electrochemical sensor for hydrogen peroxide in living cells

Molybdenum sulfide nanosheets on nitrogen-doped carbon nanowires (MoS2/CN NWs) were utilized to construct an electrochemical biosensor for hydrogen peroxide (H2O2). Polypyrrole nanowires (PPy NWs) were synthesized using a surfactant-assisted method, and few layers of MoS2 nanosheet grew on PPy NWs by a hydrothermal approach. After a sintering process, the prepared MoS2/CN nanohybrid was supposed to enhance the electrochemical catalytic performance for H2O2 resulting from the synergistic effect between the high stability of CN NWs and abundant active sites of MoS2 nanosheets. The CN NWs served as the framework for the few-layered MoS2 to form a core-shell structure which could increase the stability and electrochemical conductivity of MoS2 nanocomposite. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to characterize the crystallinity of MoS2 and the nitrogen-doped carbon nanowires. The electrochemical responses showed that the MoS2/CN NWs modified electrode has a good catalytic performance toward H2O2 determination with a wide linear range from 2 to 500 μM, and a low detection limit of 0.73 μM (S/N = 3). Moreover, the fabricated electrochemical biosensor performed monitoring of H2O2 released from A549 living cells, indicating that the MoS2/CN NWs offered a simple and convenient pathway in the fields of electrochemical sensing.