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
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)