Nanoparticles of titanium dioxide only skin deep?

摘要

In this study, the dermal penetration into minipigs of submicron and nano-sized titanium dioxide applied 5% by weight in a sunscreen was investigated. Three types of TiO2 particles were used in the study: uncoated submicron, uncoated nano and copolymer coated nano. Electron microscopy-energy dispersive X-ray analysis revealed the presence of all three types of T1O2 particles in the stratum corneum and upper follicular lumens of the treated skin samples (with more particles visible with coated nano-TiO2). TiO2 content in skin, lymph nodes, liver, spleen and the kidneys was determined using inductively-coupled plasma mass spectroscopy. Titanium levels in lymph nodes and liver from treated animals were found to be no greater than those in control animals. It is concluded that there is no significant penetration of TiO2 nanoparticles through the intact normal epidermis.