Graphene Oxide-Mediated Protection from Photodamage.

This Letter presents the unique properties of graphene oxide (GO) as a multitask material protecting from UVB-induced photodamage. Three mechanisms of GO action on fibroblast in vitro cultures are verified here: physical - a barrier blocking UV radiation; chemical - antioxidative activity; and biological - activation of cellular antioxidative defense. The changes in GO physicochemical properties appearing due to UVB exposure underpin the observed UV protection phenomena. The results reveal the simultaneous occurrence of two opposed processes, i.e., under small doses of UVB, the tested material undergoes oxidation and sp2 network rebuilding. In the vicinity of the GO surface, the locally triggered high temperature is responsible for a reduction process, while strong oxidative agents such as OH radicals cause parallel GO oxidation. This phenomenon is enabled thanks to the exceptional properties of carbonaceous materials. As a consequence, GO turns out to be a multitask UV protector increasing fibroblast survival.