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

Hydrogen peroxide (H₂O₂), 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 H₂O₂ 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 H₂O₂, 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 H₂O₂ in cells, yielding results of 1.69 × 10⁻¹⁴ M H₂O₂ /cell and 1.59 × 10⁻¹⁴ M H₂O₂ /cell for electrochemical and colorimetric detection of MCF-7 cells, and 1.67 × 10⁻¹⁴ M H₂O₂ /cell and 1.58 × 10⁻¹⁴ M H₂O₂ /cell of Hela cells, respectively. These results demonstrated high sensitivity and anti-interference capabilities, enabling quantitative detection of H₂O₂ 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 H₂O₂ in cells.