Preparation of TiO2-loaded nanocapsules and their sun protection behaviors

Titanium dioxide (TiO2) sol (TS) or TiO2 nanoparticles with chitosan shell were encapsulated to enhance their sun protection abilities. Nanocapsules loaded with TiO2 were evaluated for their ultraviolet (UV) absorption and UV protection rate. The effect of eicosapentaenoic acid (EPA) incorporation into the nanocapsules was examined in relation to UV absorption. The particle size of TiO2 crystallites in TS was below 30 nm, which was considerably smaller than that of a commercial TiO2 (P25 TiO2) particles. In the encapsulation of TiO2 with chitosan, the loading efficiencies of TS were higher than those of P25 TiO2. The sizes of the nanocapsules loaded with TiO2 particles ranged from 30 to 80 nm. The absorption range of irradiation wavelength was enlarged by the incorporation of EPA into the nanocapsules. The TS-loaded nanocapsules exhibited a high UV protection rate of up to 95% to both UV-A and UV-B.