to cis forms under ultraviolet radiation [10–13]. As a typical inorganic sunscreen, TiO2 is an effective UVB absorber [14,15]. These
nanoparticles have a considerable and rapid effect on mitochondrial function and 85 biochemical metabolites are found to be significantly altered, many of which are known to be associated with
the cellular stress response [16].
A new kind of photosensitive azobenzene compound, 4-cholesterocarbonyl-4’0
-(N,N0
-diethylaminobutyloxy) azobenzene (CDBA),
has been synthesized by our group, which could be integrated into
the liposomal membrane. There was no significant cytotoxicity on
Bel 7402 cells and NIH 3T3 cells even if the concentration of CDBAwas increased to 1.2 lmol mL1 [12]. In this paper, the storage
stability of CDBA-liposomes when mixed with some cosmetic
substrates was evaluated under different storage conditions. The
photo-isomerization of CDBA-liposomes and photo-induced release of encapsulated doxorubicin (DOX, a fluorescent molecule)
after UV irradiation for various periods with or without these sunscreen substrates were assessed. Furthermore, the long-wavelength UV (UVA) and short-wavelength UV (UVB) protective
effects of the CDBA-liposomes were evaluated by the critical wavelength method and the ultraviolet spectrophotometer method,
respectively. Finally, we also carried out in vivo tests to estimate
the UV protecting efficacy of CDBA-liposomes with nude mouse.