Polydopamine-sealed mesoporous silica nanocarriers loaded with organic UV filters for effective full-spectrum UV...

Ultraviolet radiation induces skin carcinogenesis through DNA damage and oxidative stress, driving demand for high-efficacy sunscreens. Current organic filters (e.g., octyl methoxycinnamate, OMC) suffer from narrow spectral coverage and phototoxicity. To address these limitations, we engineered OMC-loaded hollow mesoporous silica nanoparticles with polydopamine coating (OMC@HMSN@PDA). This nanoplatform achieved: (i) synergistic broad-spectrum protection, the sun protection factor (SPF) and UVA protection factor (UVAPF) up to 54 ± 0.74, 26.8 ± 6 with the concentration of 6 wt% OMC respectively, exceeding OMC@HMSN by 10.4-fold in UVB and 11.2-fold in UVA attenuation; (ii) 93.1 ± 1.2 % of DPPH and 98.5 ± 2.5 % of ABTS radical scavenging at 10 µg mL^-1, and 94.6 ± 0.03 % intracellular reactive oxygen species (ROS) suppression; and (iii) prevention of the payload leakage and photo-instability of OMC, resolution of OMC's phototoxicity with above 80 % cell viability in vitro. In vivo studies demonstrated prevention of UV-induced epidermal hyperplasia and lower inflammation. This technology establishes a promising approach for photoprotection integrating UV filtering, antioxidant activity, and enhanced safety.