Many of our readers are familiar with the controversy surrounding the use of nanoscale TiO2 particles in sunscreens and cosmetics.  Several organizations claim that topically applied nanoscale TiO2 particles have the ability to penetrate into living skin, enter individual cells, and damage DNA.  The debate eventually found its way to the Food and Drug Administration which regulates these products. FDA held a public hearing covering the issue in October 2006 and also solicited expert submission across a variety of fields.  Companies have since expended a serious amount of time and effort to assure the public and government that such concerns are unfounded. 

In a recent research study, scientists at Stony Brook University and Columbia University claim to have developed a polymer coating for nanoscale TiO2 particles "which completely protects DNA" against potential dermal penetration damage.  The polymer coating is made of oligomeric proanthocyanidins anti-oxidant molecules bound in an anionic polymer which is then used to coat the nanoparticles.  Apparently, the "multi-component polymer coating absorbs the photoelectron generated when titania nanoparticles are exposed to UV light and blocks the photocatalytic activity that causes DNA damage."

Source: Chemical Science, September 27, 2007.