Nanotech News

October 17, 2005

Gold Nanoparticles Show Potential
for Noninvasive Cancer Treatment

A father-and-son team of researchers from the University of California, San Francisco, and Georgia Institute of Technology have shown that targeted gold nanoparticles combined with a subsequent laser ablation can kill oral cancer cells. Building on their previous work that used gold nanoparticles to detect cancer, the investigators now are heating the particles and using them as agents to destroy malignant cells. Their study findings are reported in the journal Cancer Letters.

"In an earlier study we showed how gold nanoparticles could be bound to malignant cells, making cancer detection easier. Now we have examined how the particles' ability to absorb light helps kill those cancer cells," said principal author Ivan El-Sayed, M.D., of the UCSF Medical Center.

Many cancer cells have a protein, known as epidermal growth factor receptor (EGFR), distributed widely on the outside of their cell membranes. In contrast, healthy cells typically do not produce much of this protein. By attaching gold nanoparticles to an antibody for EGFR (anti-EGFR), the researchers were able to get the nanoparticles to specifically attach themselves to the cancer cells.

In the new study, the researchers incubated two oral squamous carcinoma cell lines and one benign epithelial cell line with anti-EFGR conjugated gold nanoparticles and then exposed them to continuous visible light from an argon laser. "The malignant cells required less than half the laser energy to be killed than the benign cells," said Ivan El-Sayed. "In addition, we observed no photothermal destruction of any type of cell in the absence of gold nanoparticles at these low laser powers."

When combined with the researchers' earlier work using the same nanoparticles to detect oral carcinoma, this research points the way to a multifunctional nanoparticle for detecting and treating oral cancer. "We now have the potential to design an 'all in one' active agent that can be used to noninvasively find the cancer and then kill it," added Ivan El-Sayed. "This holds great promise for a number of types of cancer."

This work is detailed in a paper titled, "Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles." An abstract is available through PubMed.
View abstract.