Probing trace of intracellularly-originated hydrogen peroxide based Pt–Cd bimetallic nanozyme on an enzyme-free electrochemical sensor

Measurement of endogenous cellular hydrogen peroxide (H2O2) can provide information on cellular status, and help to understand cellular metabolism and signaling processes, thus contributing to elucidation of disease mechanisms and new diagnostics/therapeutic approaches. In this work, Pt–Cd bimetallic nanozyme was successfully prepared via the solvothermal synthetic method for sensitive detection of H2O2. The synthesized Pt–Cd bimetallic nanozyme could exhibited good electrochemical activity. Then, the materials were analyzed for the electrochemical properties and catalytic properties of H2O2 by cyclic voltammetry and chronoamperometry, respectively. Results indicated that the synthesized nanozyme had superior sensitivity (295 μA⸳mM−1⸳cm−2) and selectivity toward H2O2 with a detection limit of 0.21 μM. Further, the Pt–Cd bimetallic nanozyme displayed good electrochemical properties compared to platinum catalysts alone. The application was extended to determine the produced H2O2 from human hepatocellular carcinoma cells (HepG2) and normal hepatocyte (LO2) samples after ascorbic acid stimulation, thus enabling the early warning of cellular carcinogenesis. This strategy promises simple, rapid, inexpensive and effective electrochemical sensing and provides a new pathway for the synthesis of bimetallic nanozymes to construct an electrochemical sensor for the sensitive detection of H2O2. [Display omitted] •An enzyme-free electrochemical sensor was designed to detect hydrogen peroxide.•Intracellularly-originated hydrogen peroxide with human hepatocellular carcinoma cells.•Pt–Cd bimetallic nano-hybrids used as the nanozymes for electrocatalytic sensing.•Superior sensitivity, good reproducibility, high specificity and acceptable accuracy.