Gold and Drugs. This Time It's A Good Thing

Using tiny particles of gold and waves of infrared light, MIT researchers have developed a drug-delivery system that allows multiple drugs to be released in a controlled fashion. This would be a great deal of help when treating diseases commonly treated with more than one drug, according to the researchers. These 'drug cocktails' have been proven to be very effective ways of comating some of our most serious illnesses. "With a lot of diseases, especially cancer and AIDS, you get a synergistic effect with more than one drug," said Kimberly Hamad-Schifferli, assistant professor of biological and mechanical engineering at MIT.

How Is This Different From What We Can Do Now?

Delivery devices already exist that can release two drugs, but the timing of the release must be built into the device -- it cannot be controlled from outside the body. The new system is controlled externally and theoretically could deliver up to three or four drugs. The technique takes advantage of the fact that when gold nanoparticles are exposed to infrared light, they melt and release drug payloads attached to their surfaces. Nanoparticles of different shapes respond to different infrared wavelengths, so "just by controlling the infrared wavelength, we can choose the release time" for each drug, said Andy Wijaya, graduate student in chemical engineering.

How Do They Melt Just One At A Time? 

ImageThe team built two different shapes of nanoparticles, which they call "nanobones" and "nanocapsules." Nanobones melt at light wavelengths of 1,100 nanometers, and nanocapsules at 800 nanometers.These two types have seperate melting wavelengths, and they can be melted at will.  (Image Credit)