Nanoparticles created with on-off switch for cancer drugs

What separates nanotechnology from simple use of nanoparticles is the ability to engineer nanoscale material to perform specific functions--whether through manipulation of size, surface treatment or ability to react to a set of stimuli such as pH levels or application of a magnetic field. You get all of these elements going, and then you just might be straying into "nanomachine" territory. And that's where we find a team of investigators from the University of California, San Diego, who created a nanoparticles-within-nanoparticles that can be switched on and off remotely to release anti-cancer drugs.

Here's how it works: A research team led by Sungho Jin created multi-component nanoparticles stuffed with magnetic nanoparticles and the drug anti-cancer drug camptothecin. All of this is trapped within a silica nanoparticle. Then, the researchers applied a magnetic field outside the body, which cues the magnetic iron oxide nanoparticles to release the camptothecin directly onto the tumor. At moderate magnetic field strengths the nanoparticles not only accumulate in the vicinity of a tumor but also penetrate into the tumor mass, the scientists report in the journal Nano Letters.

Initial results were so successful that the researchers injected the nanoparticles into mice implanted with human breast tumors. They subjected the animals to three 8-minute exposures to radiofrequency irradiation. The treated animals experienced a marked reduction in the size of their tumors and experienced no noticeable side effects.

- here's the NCI Alliance for Nanotechnology in Cancer release
- and read the abstract in Nano Letters