UVB exposure enhanced the dermal penetration of zinc oxide nanoparticles and induced inflammatory responses through oxidative stress mediated by MAPKs and NF-κB signaling in SKH-1 hairless mouse skin

Besides titanium dioxide (TiO2), zinc oxide (ZnO) nanoparticles (NPs) are commonly used in sunscreen formulations as protective agents against exposure to ultraviolet radiation. Although the majority of prior studies have concluded that NPs do not penetrate healthy skin, compromised skin slightly enhanced metal oxide NP penetration. However, a question arises regarding the possible toxic consequences if consumers who had applied sunscreens containing ZnO-NPs were exposed to environmentally relevant doses of UVB. Considering this, we planned a study where SKH-1 hairless mice were topically exposed to a 5% and/or 10% dose of ZnO-NPs (