Friday, January 2, 2009

MIT: Gold, infrared light may enable drug delivery

By Marc Songini

MIT researchers are testing gold nanoparticles and infrared light to potentially create a drug-delivery system that can remotely control the release of multiple drugs.

Using these nanoparticles, doctors could treat patients more efficiently by targeting diseases that respond better to a combination of drugs than to individual ones, the researchers claimed. The new technique relies on exposing gold nanoparticles to infrared light, melting them and allowing them to release a chemical payload bonded to their surfaces.

Doctors are now able to achieve a “synergistic” effect by using multiple drugs when treating ailments such as cancer and AIDS, stated MIT researcher Kimberly Hamad-Schifferli, assistant professor of biological and mechanical engineering. While devices already exist to administer two drugs simultaneously, they require a time mechanism to be embedded inside them. However, the MIT researchers believe using the tiny particles, doctors can have a new system that controls the release from outside the patient’s body and that allows three or four drugs to be released.

Additionally, these nanoparticles are formed into different shapes and respond to varying infrared wavelengths. By adjusting the infrared wavelengths, the researchers found they could choose the specific release time for each drug. For the experiment, the MIT team created nanoparticles with two different shapes: “nanobones” and “nanocapsules.” The nanobones melt at light wavelengths of 1,100 nanometers; nanocapsules melt at 800 nanometers.

The researchers also tested the particles with DNA payloads. Hypothetically, as many as four differently shaped particles can be created that release their payloads at varying wavelengths, claimed the researchers.