Ultrasensitive electrochemical detection of H2O2 in living cells based on ultrathin MnO2 nanosheets

Using a facile and efficient method, two-dimensional (2D) ultra-thin MnO2 nanosheets were successfully prepared. Due to the large specific surface area and mesoporous structure, MnO2 nanosheet is a good candidate for use as an enhanced electrochemical sensing material. MnO2 nanosheets were immobilized onto glassy carbon electrodes with Nafion film to construct a H2O2 electrochemical nonenzymatic sensor. Amperometric study showed MnO2 nanosheets exhibited very high electrocatalytic activity towards H2O2 reduction. A very low detection limit (5 nM) was reached with a wide linear range (25 nM–2 μM and 10–454 μM) and a high sensitivity of 3261 mA M−1 cm−2. The fabricated H2O2 sensor also exhibited excellent selectivity, good reproducibility and long-time stability. Furthermore, the constructed high sensitive sensor was successfully applied to perform real-time monitoring trace concentration of H2O2 released by SP2/0 cells, indicating that MnO2 nanosheets provide a new platform for developing high performance electrochemical sensors in biological applications.