Scientists have found a method to detect cancer by combining the use of gold nanoparticles with Raman spectroscopy — a technique developed by Indian physicist C.V. Raman seven decades ago. The research by Sanjiv Gambhir and colleagues at Stanford University in the US reported in Thursday’s Science Translational Medicine moves nanomedicine one step closer to reality. Gold-silica nanoparticles — that are several thousand times smaller than the thickness of human hair — combined with Raman spectroscopy can safely detect colorectal cancer, according to their study done in mice.
They believe that their tiny gold balls — coated with materials designed to be detected with a Raman spectroscope — for finding colorectal and possibly other cancers would be ready for human trials within a year and a half.
The gold nanoparticles have little hook-shaped peptides that latch onto cancer cells, while any free-floating nanoparticles wash away.
During an endoscopy, doctors can spot the cancer by seeing where the gold-silica nanoparticles have stuck. In molecular imaging, molecules are injected into the body that home in on molecules that might be indicative of cancer. But once they home in on those molecules, they have to produce a large signal that can be detected outside the human body. At Stanford, the researchers developed particles made out of gold that go into the bowel to detect colorectal cancer.
The gold acts as an amplifier to produce a very heavy or strong Raman signal from the gold particle after it has latched onto a colorectal cancer. The characteristic signals can be detected by a Raman spectroscope.
Nanoparticles of this type were originally used in currency inks to make them difficult to counterfeit. Embedded in currencies, the nanoparticles scatter light in unique patterns called Raman spectra when scanned for authenticity. But Gambhir’s laboratory co-opted these gold-silica nanoparticles for a completely different use: bioimaging to detect colorectal cancer.