Raman Nanoparticle-Aided Imaging of Tumors Moves Closer to Human Trials
In 2008, a team of investigators at Stanford University's Center for Cancer Nanotechnology Excellence demonstrated that they could use a technique known as nanoparticle-aided Raman spectroscopy to look at microscopic structures, including nascent tumors, deep inside the body. That team has now conducted extensive preclinical tests and shown that the gold nanoparticles can be safely administered into the colon and used with a Raman endoscope to image the inside of the large intestines.
Reporting their work in the journal Small, Sanjiv Sam Gambhir and his colleagues describe the experiments they conducted using radioactively labeled gold nanoparticles to track the accumulation of the nanoparticle imaging agents inside mice. Dr. Gambhir is the principal investigator of the Stanford Center for Cancer Nanotechnology Excellence, one of nine such centers included in the National Cancer Institute's Alliance for Nanotechnology in Cancer.
After labeling the nanoparticles with a radioactive isotope of copper, the investigators used micro-positron emission tomography (micro-PET) to image the nanoparticles' location in the body. When the nanoparticles were injected intravenously, they accumulated in a variety of organs, with almost 10 percent of the dose of nanoparticles ending up in the liver. In contrast, when the nanoparticles were injected rectally into the colon, less than 1/10th of 1 percent of the nanoparticles accumulated outside of the large intestine even as far as two weeks after injection. In the colon, the nanoparticles could be visualized using an endoscope modified to detect Raman signals.
This work, which is detailed in a paper titled, "Preclinical Evaluation of Raman Nanoparticle Biodistribution for their Potential Use in Clinical Endoscopy Imaging," was supported in part by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. An abstract of this paper is available at the journal's website.