Using Gold to Deliver a Cancer Drug

What does a Yew tree, gold, and nanotechnology have in common? A lot more than you would think!

First, the Yew tree's bark has provided us with one of the most widely prescribed anti-cancer drugs: Taxol. It's been prescribed since 1967 for breast, ovarian and other cancers.

Second, nanotechnology has given researchers the ability to form a tiny gold "ball" that the Taxol is then attached to.

In an amazingly complex procedure, researchers at Rice University have developed this new drug delivery system that has significant implications for the war on cancer. Although this particular drug has been used for the past 40 years, and is very effective at stopping cancer cell development, it also affects fast-growing healthy cells, too. A couple of examples of this would be the hair loss and immune system suppression many patients experience as side effects of Taxol. As a result, scientists are always looking for optimal delivery systems in order to prevent destruction of non-cancerous cells.

This "gold ball" delivery system reads like something out of a science fiction story. In layman's terms, this is how it works in a nutshell:

- all living cells contain microtubules that form the inner framework of the cell
- before a cell can divide and multiply, it must remove the microtubles
- the cancer cells must destroy these microtubule structures before they divide
- Taxol attaches itself to the microtubules, preventing further cell division
- the cancerous tumor is then stopped dead in its tracks

The "trick" is being able to precisely deliver the drug directly to the cancer cells and not harm the healthy ones. This is where the gold ball comes into play. The researchers were able to form microscopic balls from gold that are only slightly wider than the width of a DNA strand.

They then attach a precise and constant number of Taxol molecules to each ball, use nanotechnology. The benefits of this process derive from striving to achieve a uniform dispersion, solubility and bioavailability. The Taxol nanoparticles are all oriented so that their specific regions that bind with microtubules are maximized. When delivered to the tumor site, the gold spheres containing dense amounts of Taxol lock onto the microtubules and jam up the works.

Virtually everyone knows someone who has or had breast cancer or ovarian cancer. While we go about our daily lives, these research scientists are feverishly working to find that Holy Grail: a cure for cancer.

The research is available online and will appear in the Sept. 19 issue of the Journal of the American Chemical Society (J. Am. Chem. Soc. 2007, vol. 129, pgs.11653-11661).