▎ 摘　　要

Reliable H2O2 sensors for in situ cellular monitoring under drug stimulation can be developed as a powerful and versatile tool for drug evaluation. Herein, a novel electrochemical biosensor capable of detecting and quantifying H2O2 was fabricated by graphene and shape-controlled gold nanostructures. With the help of polyelectrolytes, gold exhibited hierarchical flower-like nanostructures. This kind of nanozyme material exhibited a prominent electrochemical response for H2O2. Electrocatalytic activity for H2O2 reduction with high sensitivity (5.07LOZENGE10-4 mA mu mol L-1 cm-2) and good detection capability (the lowest detection limit is 4.5 mu mol L-1 (S/N = 3)) were achieved. This electrochemical biosensor was successfully used to measure the concentration of H2O2 released from HepG2 hepatoma cells. Ascorbic acid (AA) and Camellia nitidissima Chi saponins (CNCS) were selected as model drugs, and their anticancer activities were compared by in situ monitoring of H2O2. Interestingly, the electrochemical sensor showed remarkable sensitivity, accuracy, and rapidity compared with the traditional enzymatic detection kit. In brief, the as-synthesized nanostructured H2O2 sensors can be applied to assess the antitumor properties of candidate drugs and inspire developments for personalized health care monitoring and cancer treatment.