Role of particle coating in controlling skin damage photoinduced by titania nanoparticles

Abstract

TiO(2) nanoparticles hazard is associated to their photocatalytic activity causing release of DNA damaging ROS (Reactive Oxygen Species), lipid peroxidation and skin damage. Various coatings have been proposed to minimize photocatalysis, while keeping the potential to block UV radiations. Uncoated and variously coated commercial nano-titania have been classified on the basis of UVB-induced lipoperoxidation of linoleic acid. A selection of the most and the least protective specimens was then examined by ESR (Electron Spin Resonance) to evidence the presence of surface paramagnetic centres and the release of ROS in aqueous suspensions (spin trapping). Paramagnetic centres and ROS were correlated with the extent of lipid peroxidation. When tested on porcine skin (mimicking the human one), titania acted as on linoleic acid. The combined use of lipid peroxidation of simple fatty acids with ESR analysis is here proposed as a possible screening tool for the evaluation of the potential toxicity of nano-titania in sunscreen preparations.

The influence of surface charge and photo-reactivity on skin-permeation enhancer property of nano-TiO2 in ex vivo pig skin model under indoor light

“…Negatively charged AR-SL and AR-SL-S were both easily removed by washing, but differentiation in term of surface reactivity was observed. The imperfect coating (Carlotti et al, 2009) and the lipophilic nature of AR-SL could explain the high rate of lipid peroxidation measured in the cell-free test. However, despite this significant chemical reactivity, AR-SL, when contacted with skin, did not induce structural alterations of the lipids in the stratum corneum (Raman spectroscopy), nor yielded an enhancement in drug permeation.…”

“…Indeed, the risk of damage to DNA and RNA, caused by the photocatalytic effect of nano-TiO2 after absorption of UV light, can be prevented by particles coating with organic and inorganic materials (Serpone et al, 2007). They are expected to reduce the oxide photo-reactivity (Carlotti et al, 2009), and, mostly in the case of silane-coated TiO2, to enhance the compatibility with the lipophilic ingredients of the cosmetic preparations.…”

“…As a consequence of such ability to impregnate the first layers of SC as well as to form complexes with proteins and to induce the formation of free radicals (Borm et al, 2006;Turci et al, 2013;Carlotti et al, 2009Carlotti et al, , 2007Fenoglio et al, 2013Fenoglio et al, , 2011, nano-TiO2 could increase transdermal permeation of drugs or active ingredients, when used as an excipient in pharmaceutical products or as UV filter in sunscreen lotions.…”

Inhibition of the ROS-mediated cytotoxicity and genotoxicity of nano-TiO2 toward human keratinocyte cells by iron doping

“…Therefore, commercial nano-TiO 2 are generally coated with inert materials (Lee et al 2007;Landsiedel et al 2010) which inhibits the formation of radical species and singlet oxygen by preventing the contact of the TiO 2 surface with oxygen and water. However, not all the coatings are equally efficient in preventing the release of surface-derived ROS (Sayes et al 2006;Brezova et al 2005;Carlotti et al 2009;Tiano et al 2010;Buchalska et al 2010). Antioxidant ingredients are also added to the formula to mitigate the oxidative properties of photogenerated ROS (Carlotti et al 2009).…”

“…However, not all the coatings are equally efficient in preventing the release of surface-derived ROS (Sayes et al 2006;Brezova et al 2005;Carlotti et al 2009;Tiano et al 2010;Buchalska et al 2010). Antioxidant ingredients are also added to the formula to mitigate the oxidative properties of photogenerated ROS (Carlotti et al 2009). One possible alternative strategy is to use TiO 2 forms which are less reactive such as rutile.…”