US researchers have produced a powerful new tool for the delivery of anti-cancer drugs.
Using a gold nano-particle core barely bigger than a strand of DNA, Rice University's Eugene Zubarev has found a way to link dozens of molecules of the drug paclitaxel to the surface of the particle to turn it into a molecular mine. Normally, administering the right doses of chemotherapy can be problematic owing to difficulties with the solubility of some drugs, and the ability of drugs to penetrate tumours and disperse uniformly throughout the body, and paclitaxel (marketed as Taxol) is no exception. But because the new nano-balls are loaded with a uniform number of drug molecules they should help to overcome some of these difficulties.
Taxol achieves its anti-cancer effect by binding to structures inside cells called microtubules, which behave like internal scaffolding. To divide cells need to dismantle and rebuild some of these microtubules, but Taxol stops this from happening by anchoring itself to them using a region at one end of the drug molecule. But this key region can be damaged when attempts are made to anchor the drug to other molecules or nanoparticles. To get around this problem the Rice University team developed a chemical shroud that could protect the Taxol molecules while they were being linked to the gold particle. Once the molecules were in place the shroud was chemically removed.
The next step is to determine the effectiveness of the particles compared with unmodified drug molecules. "We are already working on follow-up studies to determine the potency of the paclitaxel-loaded nanoparticles," says Zubarev.