Over the past few decades engineered nanoparticles (<100 nm) have become available in commercial products and manufacturing, therefore increasing the likelihood of deliberate human exposure to these particles. Currently, there are conflicting reports as to if nanoparticles can penetrate the skin. A novel in vitro flexing diffusion cell (CutaFlex^TM) was designed to investigate the effect of flexing on skin barrier function as well as on the potential for nanoparticle penetration. Results indicated that in vitro flexing of skin maintained barrier integrity. Furthermore, preliminary results found no difference in in vitro nanoparticle absorption between flexed and un-flexed skin.