Fig. 4: The influence of the variant UVA intensity on A-CXL efficacy of C₃N₄ QDs.

a Schematic of a simple operation flow chart of A-CXL evaluation including variable experimental condition. b Photos depicting the digestion behavior of the cornea in the presence of collagenase II over time. c Quantitative analysis of the undigested corneal disc area over time (mean ± SD, PBS group, n = 6; 3 mW cm⁻² and 6 mW cm⁻² groups, n = 4; 9 mW cm⁻² and 18 mW cm⁻² groups, n = 6; two-way ANOVA multiple comparison test, the absence of a P-value indicates no statistical difference between the groups (p > 0.05)). d The dry weight of the residual cornea (mean ± SD, PBS group, n = 6; 3 mW cm⁻² and 6 mW cm⁻² groups, n = 4; 9 mW cm⁻² and 18 mW cm⁻² groups, n = 6; two-way ANOVA multiple comparison test, the absence of a P-value indicates no statistical difference between the groups (p > 0.05)). e SEM images of the corneal issues in PBS and g-C₃N₄ QDs groups (The experiment was repeated three times independently with similar results).