rGO@PDA@MXene-Au@COF for electrochemical-colorimetric dual-mode sensitive detection of H2O2 in cells

Hydrogen peroxide (H 2 O 2 ), a type of reactive oxygen species (ROS) produced by cells, plays a significant role in various physiological processes. Its abnormal concentrations in human body are closely associated with cellular damage as well as a variety of major diseases. Consequently, sensitive and accurate detection of cellular H 2 O 2 concentration is of great significance in evaluating the degree of intracellular oxidative stress in human cells. In this study, a novel heterogeneous nanomaterial, rGO@PDA@MXene-Au@COF, was designed for electrochemical-colorimetric dual-mode detection of intracellular H 2 O 2 , which enhances both peroxidase and electrochemical activities, achieving lower detection limits and broader linear ranges. ESR spectroscopy, EIS resistance analysis and computational simulation were employed to verify the mechanism of the activity enhancement, and the detection conditions were optimized. The methods were subsequently applied to the determination of H 2 O 2 in cells, yielding results of 1.69 × 10 −14  M H 2 O 2 /cell and 1.59 × 10 −14  M H 2 O 2 /cell for electrochemical and colorimetric detection of MCF-7 cells, and 1.67 × 10 −14  M H 2 O 2 /cell and 1.58 × 10 −14  M H 2 O 2 /cell of Hela cells, respectively. These results demonstrated high sensitivity and anti-interference capabilities, enabling quantitative detection of H 2 O 2 in complex cellular environments. Furthermore, the similarity in results between the two methods confirms their mutual accuracy and reliability. This work provided a novel approach for designing multifunctional nanomaterials and detecting H 2 O 2 in cells.