And increase their overall efficiency

May 24, 2010 09:11 GMT  ·  By
Small chemical ornaments (cones) slow the release of anti-cancer antibodies (blue) from this functionalized mesoporous silica (orange)
   Small chemical ornaments (cones) slow the release of anti-cancer antibodies (blue) from this functionalized mesoporous silica (orange)

Skin cancer can be more efficiently addressed by placing drugs inside modified silica particles, a new study shows. Researchers demonstrated that honeycomb-like structures made of custom-built silica can safely harbor antibodies aimed at cancer tumors, until they reach their destination. Generally, the human immune system tends to attack any foreign molecules that enter the body, regardless of whether they are really dangerous or not. But the drugs can be protected using silica coatings, which keep them safe until they are delivered to the site of the tumor. This means that more drug particles make their way to the cancer, thus increasing the medicine's efficiency.

The new study was focused on skin cancer, and was conducted on unsuspecting lab mice. The complete results appear in the May 3 online issue of the esteemed Journal of the American Chemical Society (JACS). “We are very excited by our preliminary results. We plan to do some additional, larger studies with animals. We hope the results hold up well enough to take it to clinical trials somewhere down the road,” says expert Chenghong Lei, who holds an appointment as a biochemist at the US Department of Energy's (DOE) Pacific Northwest National Laboratory (PNNL). Researchers here conducted the study alongside colleagues from the University of Washington.

“The silica's mesoporous nature provides honeycomb-like structures that can pack lots of individual drug molecules. We've been exploring the material for our energy and environmental problems, but it seemed like a natural fit for drug delivery,” says Jun Liu, who is also a material scientist at the PNNL. At this point, investigators are working on determining how the immune system reacts, and intensifies its struggle against cancer, when drugs are delivered in this manner. These studies are conducted on mice as well, as the rodents develop cancer and respond to treatments very similar to the way we do.

“We want to understand the mechanism, because not much is known about how the slowly leaked antibodies induce changes in the immune system or in the micro-environment of the tumor,” explains Karl Erik Hellstrom, the leader of the tumor biology group at the University of Washington. He adds that preliminary test results were very promising. Mice injected with silica-encased antibodies retained a lot more of the drugs and around the tumors 2 to 4 days after receiving the shot, when compared to animals that only received the antibodies, without any encasing.