Atomic-Thick PtNi Nanowires Assembled on Graphene for High-Sensitivity Extracellular Hydrogen Peroxide Sensors.

H2O2 sensors with high sensitivity and selectivity are essential for monitoring the normal activities of cells. Inorganic catalytic nanomaterials show the obvious advantage in boosting the sensitivity of H2O2 sensors; however, the H2O2 detection limit of reported inorganic catalysts is still limited, which is not suitable for high-sensitivity detection of H2O2 in real cells. Herein, novel atomic-thick PtNi nanowires (NWs) were synthesized and assembled on reduced graphene oxide (rGO) via an ultrasonic self-assembly method to attain PtNi NWs/rGO composite for boosting the electroanalysis of H2O2. In 0.05 M phosphate-buffered saline (pH 7.4) solution, the as-prepared PtNi NWs/rGO shows an extraordinary performance in quantifying H2O2 in a wide range of concentrations from 1 nM to 5.3 mM. Significantly, the detection limit of PtNi NWs/rGO reaches unprecedented 0.3 nM at an applied potential of -0.6 V (vs Ag/AgCl), which enables the detection of traced amounts of H2O2 released from Raw 264.7 cells. The excellent performance of H2O2 detection on PtNi NWs/rGO is ascribed to the high-density active sites of atomic-thick PtNi NWs.