Fig. 2: The oxidative stress-related properties of P-CHNPs.

a The absorption spectra of the mixture solution of ABDA and P-CHNPs under light irradiation for different time. Inset: absorption variation of mixture solution at 399 nm with the increment of irradiation time. [P-CHNPs] = 50 μg mL⁻¹, [ABDA] = 50 μM. b The fluorescence spectra of RDPP in different mixture solutions. [P-CHNPs] = 100 μg mL⁻¹, [RDPP] = 30 μM. c The consumption rate of ABDA in different mixture solutions under light irradiation. [ABDA] = 50 μM, [P-CHNPs] = 50 μg mL⁻¹. d UV-vis absorption spectra of TMB in different mixture solution (pH 6.5) under light irradiation. Inset: absorption variation (650 nm) of TMB, H₂O₂ and P-CHNPs mixture solution with different pH values. [P-CHNPs] = 50 μg mL⁻¹, [TMB] = 800 μM, [H₂O₂] = 300 μM. e Optical density value variations of GSH Colorimetric Assay Kit treated with different concentrations of P-CHNPs. ***P < 0.001, n = 5. f The high-resolution XPS of P-CHNPs reacted with GSH for Fe 2p. L: light irradiation (400–700 nm, 70 mW cm⁻², 20 min), NPs: P-CHNPs, RD: RDPP