DNA is obviously C188-9 nmr one of the key targets for UV-induced damage in a variety of organisms which is traditionally attributed to the direct absorption of UV photons by nucleic acids and protein [1, 4]. And the exposure of polymers to UV radiation may produce degradation discoloration and/or brittle fracture [5]. This is due to the UV irradiation-induced chemical reactions such as chain scission, crosslinking, oxidation or bond cleavage in the polymers [6–8]. All these damages may be undesirable due to their adverse impacts on the safety of organisms and the PARP inhibitor period of use of polymers. So, many organic and inorganic filters

have been used to absorb and scatter UV radiation [3, 9]. Titanium dioxide (TiO2), which can be either amorphous or crystalline [10], is used extensively in numerous applications, such as bone tissue engineering [11], bactericidal agents [12] and cosmetics [13]. The light absorption properties of anatase and rutile TiO2 are excellent since their absorption (approximately 400 nm) falls between the visible and UV regions [14]. Especially, ultrafine rutile TiO2 particles (< 100 nm) were used as a functional nanoscale additive because of its potential for the wide range Q-VD-Oph (both UVB and UVA regions) of UV-ray shielding by their

absorption, scattering and reflecting properties [15]. Once TiO2 is exposed to UV radiation, an electron is promoted from

the valence band to the unoccupied conduction band, creating excitons [16]. Rayleigh’s theory implies that shorter wavelengths of light are more efficiently scattered by smaller particles [17]. However, the smaller size leads to higher values of surface area which presents high surface energy and Dehydratase activity, so the nanoparticles tend to form agglomeration [18–20]. Particle aggregates in composite materials would decrease adhesion between nanoparticles and polymeric materials, which will result in an early failure at the interface and thus increase the susceptibility to physical and mechanical failure [21, 22]. To achieve proper dispersion of nanoparticles in polymer matrix and to yield a better compatibility between the nanoparticles and polymeric materials, several groups have attempted to prevent the aggregation by modifying the surface groups of nano-TiO2 with different reagents including the silane coupling agent [23, 24], the hydrolysis-condensation reactions (sol-gel method) [12] and in situ bulk polymerization [25, 26]. Several polymers have been mixed with nano-TiO2 successfully including polystyrene (PS) [27], polythiophene (PTh) [28], poly(methyl methacrylate) (PMMA) [25], etc. Polyester resin has been widely studied as they possess many advantages including good mechanical properties, transparency, remarkable durability and flexibility [29, 30].