Light-Switched Drug Delivery

Biomedicine

(Page 2 of 2)

Wednesday, October 7, 2009
By Rachel Kremen

A paper published in the October issue of the journal Small outlines the research, which was conducted with other researchers from Jacobs University Bremen and the Max Planck Institute of Colloids, also in Germany.

Organic chemist Jean Fréchet and colleagues at the University of California, Berkeley, have created capsules that work using a similar approach--employing carbon nanotubes that heat up when exposed to laser light.

Gold nanoparticles have also been used before, notably by Naomi Halas, professor of chemistry and director of the Laboratory for Nanophotonics at Rice University. Halas describes the European microcapsule work as "very important research," because it shows that peptides can be successfully delivered into living cells. "Peptides usually do not diffuse through cell membrane, so a cell usually only has the proteins that it makes," she says.

In addition to drug delivery, Halas says the light-release approach could be useful in the lab. "It allows you to look at various cellular functions in a quantitative way," she says. For example, researchers can carefully time the release of specific amounts of drugs and see what happens to the affected cell.

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Robert Langer, an Institute Professor at MIT, agrees that as a tool for in vitro experiments, the microcapsule is "novel" and useful. But he notes that the research has a "tremendous" way to go in addressing safety concerns before it can be used in humans.

Recently, Halas began studying the mechanics of the light-induced release. "There's a gentle heating that occurs," she says, although in her experiments the heat wasn't enough to kill the cell. The ambient temperature of the cell remains the same, and only the surface of the nanoparticle gets warmer.

Springer plans to repeat the experiment using different kinds of cells and peptides and characterizing what happens in greater detail. He is also working on a paper outlining another approach that allows the capsules to release the drugs in a predictable fashion but without the use of laser light. Such an approach could be particularly helpful for delivering drugs deep within the body, where light cannot easily penetrate.

Sukhorukov hopes to decrease the amount of light required to release the drug. The cells tend to survive the experiments, he says, "but the power of the light is a little bit too high, I think."