Interaction of nanomaterials with skin: Aspects of absorption and biodistribution

Skin is an important route of exposure to chemicals after occupational, environmental and consumer product usage, routes also pertinent to nanomaterial exposure. Knowledge of the rate and extent of absorption is required for risk assessments to be made. The primary barrier to chemical absorption is the stratum corneum. The basic question to be answered is how nanomaterial absorption compares to existing paradigms of chemical absorption. Initial studies using topically applied quantum dots suggest that absorption is minimal, yet particle characteristics and species differences exist. If nanomaterial is absorbed via any route of administration, distribution to skin may also occur as was demonstrated in isolated perfused skin studies. Research is beginning to be conducted to define the mechanistic framework describing nanomaterials biodistribution using pharmacokinetic models.