A sun cream that mops up sun-generated free iron in the skin could heal sun burn and help prevent skin cancer, claim UK chemists.

A 'massive amount' of free iron is released in skin cells that are exposed to high doses of sunlight, said Charareh Pourzand at the University of Bath. This free iron can catalyse the generation of more harmful free radicals that cause severe cell damage, she said. 

Pourzand's team added a chelator to sun cream that would bind and export iron. The trick was to find a chelator that could do this without exporting the iron needed for essential cellular processes, such as oxygen transport by red blood cells. The prototypes they arrived at, which are currently in lab trials, comprise caged iron binding sites that release the chelators only in response to UV light.

The iron chelator compounds are derived from salicylaldehyde isonicotinoyl hydrazone and pyridoxal isonicotinoyl hydrazone. The researchers report that the concentration of free iron, and the cell damage with which it is associated, was significantly decreased following exposure to a combination of the prototypical compounds and physiologically relevant UVA doses.