article: Age-related macular degeneration (AMD) is the leading cause of sight loss in the developed world. Patients are usually treated with ongoing monthly injections directly into their eyes. Australian and Chinese researchers believe gold nanoparticles could help better deliver drugs to the eye. Their study, published this week in the chemistry journal Angewandte Chemie, tested how a hydrogel filled with gold nanoparticles reacted when exposed to light. The researchers found the gel softened and released a dose of sight-restoring drug when it warmed by a only few degrees under the light. The process reversed when the light disappeared, hardening the gel and preventing the drug's delivery. The biological activity of the protein-based drug was "highly retained" after its release, the study said. Researcher Johan Basuki, from Australia's government-backed CSIRO, hoped the new drug delivery system would let AMD patients have injections less frequently - potentially once every six months. "The idea is to develop a 'drug reservoir' that can be implanted in the eye and then use visible light to trigger the drug that is embedded in the hydrogel," Dr Basuki said. "To do that we are using gold nanoparticles which have been known as a safe, inert, non-reactive component in the biomedical field." Nanoparticles, typically 1000 times thinner than a human hair, are too small to see with a microscope. The preliminary safety tests were conducted on rabbits, but further research is needed before human trials will be considered. The joint project between CSIRO and independent Chinese researchers is seeking investors to take research to the next stage. "In order to understand the function in the human body, I think we need to do a long-term study," Dr Basuki said. "The beauty of this versatile system is that the components are already FDA-approved, so they are safe for clinical use." Researchers are also investigating possible uses for the technology in agriculture, to fight cancer, and for use in personal care.
summary: Gold nanotechnology could help reduce the number of injections needed to treat a common form of blindness, researchers believe.