Sudipta Seal at the University of Central Florida in Orlando was testing cerium oxide nanoparticles, or nanoceria, for use as a catalyst to remove grime from oven walls, when he realised they might have medical applications.
Surprisingly, not only did nanoceria not irritate the eyes of rats and rabbits, in some cases they helped protect cells from light damage (New Scientist, 30 August 2003, p 16). Hence Seal realised that nanoceria might make a good vessel for delivering drugs directly into the eye.
Glaucoma involves an abnormal build-up of fluid inside the eye. Existing eye-drop treatments contain chemicals that don't attach to transport proteins very effectively, so only a small amount gets through the cornea. Now Seal and colleague Sanku Mallik have successfully combined nanoceria with a compound that blocks the hCAII enzyme, which is involved in producing fluid inside the eye (The Journal of Physical Chemistry B, DOI: 10.1021/jp067666l).