鈥淟ook up, I鈥檓 just going to drip oven cleaner into your eye.鈥�
If you heard this from your doctor, you would probably run screaming from the consulting room. But drops containing a substance commonly used to polish glass and remove grease could be used to treat glaucoma.
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. 鈥淏efore using any nanoparticles we have to check for toxicity,鈥� he says. Surprisingly, not only did nanoceria not irritate the eyes of rats and rabbits, in some cases they helped protect cells from light damage (New 杏吧原创, 30 August 2003, p 16). 鈥淲e realised that nanoceria might make a good vessel for delivering drugs directly into the eye,鈥� says Seal.
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Glaucoma involves an abnormal build-up of fluid inside the eye. Existing eye-drop treatments contain chemicals that don鈥檛 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).
At around 10 nanometres wide, the nanoceria are the right size and shape to penetrate the cornea. 鈥淲e hope to have a high concentration of the drug reaching inside the eye, also allowing us to cut down on the dosage needed,鈥� says Mallik.
