Progress and Challenges in Quantifying Skin Permeability to Nanoparticles Using a Quantum Dot Model

Increases in the research and consumer applications of nanoparticles means an increased opportunity for human skin contact. As researchers work to evaluate the most important factors in assessing nanoparticle skin penetration risk, there are common pitfalls or noise factors that can easily complicate interpretation of results and induce ambiguity. We first look at the impact of time course on skin barrier impairment, as different treatments have immediate or delayed responses. The next important factor is the skin model, as the ability to relate animal model or ex vivo tissue data to in vivo human skin susceptibility to nanoparticle skin penetration varies depending on the treatment used to induce a barrier defect. Upon consideration of skin barrier status, the characterization and stability of applied nanoparticles- in our case quantum dots- is the next most important factor. Once accounting for the experimental inputs, evaluation techniques for assessing skin penetration have an additional set of specific challenges that must be met or accounted for. With proper consideration, the challenge of determining nanoparticle and skin barrier effect on human skin penetration can be met.