The researchers are a father and son, working together on opposite coasts. Their study findings are reported in a recent edition (May 11) of the journal Nano Letters, published by the American Chemical Society.
Principal author is Ivan El-Sayed, MD, assistant professor of otolaryngology at UCSF Medical Center, who conducted the study with his father, Mostafa El-Sayed, PhD, director of the Laser Dynamics Laboratory and chemistry professor at Georgia Tech.
"Gold nanoparticles are very good at scattering and absorbing light," said Mostafa. "We wanted to see if we could harness that scattering property in a living cell to make cancer detection easier. So far, the results are extremely promising."
Many cancer cells have a protein, known as epidermal growth factor receptor (EFGR), all over their surface, while healthy cells typically do not express the protein as strongly. By conjugating, or binding, the gold nanoparticles to an antibody for EFGR, suitably named anti-EFGR, the researchers were able to get the nanoparticles to attach themselves to the cancer cells.
"After we added the nanoparticle-bound antibody to cells, using a simple technique known as darkfield microscopy, we saw the cancer cells light up under the microscope," said Ivan. "The healthy cells don't bind the particles well and are dark compared to the cancer. Since the particles have color, we can test multiple antibodies at the same time with a white light. Using simple optics, we can develop low cost techniques for rapid automated detection of cancer in biopsies. Further, we hope to use the scattering and absorption properties to develop techniques to detect cancer in humans without a biopsy."