Drug delivery

Researchers at the University of Melbourne in Australia have shown that nanometre sized polymer particles coated with gold can be used as a means to deliver drugs into the body.

Researchers in Australia have developed a drug delivery system that makes use of nanometre sized polymer particles coated with gold.

Professor Frank Caruso at the Department of Chemical and Biomolecular Engineering and his research team in collaboration with Trevor Smith from the School of Chemistry at the University of Melbourne in Australia were responsible for the development of the novel delivery system, it emerged this week.

Because laser light is absorbed by the gold nanoparticles, they found that by simply shining a laser on particles filled with an enzyme or a drug, the walls of the particles could be broken open and the contents released.

“By encasing drugs within the gold nanoparticle-shelled delivery vehicles, release of the active materials can be remotely controlled by shining a laser on the gold nanoparticles, which then opens the particle walls,” Professor Caruso said.

Dr. Benno Radt, a postdoctoral fellow in Professor Caruso’s team who is working on developing the delivery systems, said ‘we have already successfully demonstrated the release of an encapsulated enzyme, which was achieved on demand with a single nanosecond laser pulse.’

‘Inducing release of the delivery vehicle contents is so fast, it is feasible that large areas of interest could be scanned quickly even with a relatively low-power, low-cost laser.’

‘Also, there is no risk that the laser energy will be significantly absorbed by biological structures such as bodily organs because the absorption of the gold-coated delivery vehicles in the near infrared light region is intentionally engineered in the wavelength regime for which light has a maximum penetration depth in tissue.’

Professor Caruso said that up to now, a common approach for drug release has been to use changes in the local environment at the site where drug delivery is needed such as pH, salt, temperature or enzyme concentrations.

‘Our approach is different in that release can be triggered externally, making drug release on demand possible.’

German-based company, Nanosolutions, recently purchased the license for the high-concentration gold nanoparticle technology and have used it to formulate a gold ink, called GOLD. When a person writes with the ink the water evaporates, leaving nothing but a gold script on the page. The ink, which is now available to buy, can be used in any standard fountain pen and is, among other things, water and light resistant.