earticle

영어

There is a great concern about skin damage such as skin cancer and sunburn caused by the harmful influence of UV radiation (280-400 nm). Inorganic TiO2 is photostable, non-irritant and non- penetrative, thereby becoming a rapidly growing ingredient in the formulation of various sunblock products. However, TiO2 can block only UVB (280-320 nm) and causes the whitening effect. In contrast, ZnO blocks UVA (320-400 nm) efficiently with minimal whitening effect. Therefore, synthesis of ZnO-dopped TiO2 has increasingly been attempted to address the disadvantages of TiO2 based sunblocks. In this study, a novel strategy harnessing lysozyme-mediated biomineralization was demonstrated to synthesize three different types of TiO2-ZnO hybrid metal oxide particles (i.e. Type 1 in core-shell structure with TiO2 core and ZnO shell; Type 2 in core-shell structure with ZnO core and TiO2 shell; Type 3 with TiO2 and ZnO randomly dispersed at a molecular level). Successful synthesis of each type of TiO2-ZnO hybrid metal oxides was confirmed by SEM, TEM, ICP and XRD analyses. Each hybrid metal oxide showed enhanced UV scattering and absorbance for both UVA and UVB compared with similarly sized pure TiO2 and pure ZnO particles. Especially, Type 3 TiO2-ZnO hybrid exhibited significantly higher SPF (Sun Protection Factor) and PFA (Protection factor of UVA) than Type 1 and Type 2. These results suggest that hybridization of TiO2 and ZnO is effective in enhancing UV protection efficiency and that the design of hybrid metal oxide has critical impacts on determining its UV protection performance. In conclusion, the demonstrated novel metal oxide fabrication strategy based on biomineralization proves useful for synthesis of TiO2-ZnO hybrid metal oxides of exquisite structure which otherwise would be difficult to be realized.