Using nanoparticles designed specifically to produce a bright Raman spectroscopic signal, a team of investigators at the Center for Cancer Nanotechnology Excellence Focused on Therapy Response (Stanford CCNE) has shown that it can produce whole-body images in small animals that can reveal the location of tumors and track how these nanoparticles traffic through the body.
This work, the first to use surface-enhanced Raman spectroscopy (SERS) to provide whole-body images in a living animal, was reported in the Proceedings of the National Academy of Sciences of the United States of America.
Sanjiv Gambhir, M.D., Ph.D., principal investigator of the Stanford CCNE, led the team of investigators that used either single-walled carbon nanotubes (SWCNTs) or one of several commercially available silica-coated gold nanoparticles known as Nanoplex biotags, as SERS contrast agents. Each of the Nanoplex biotags produced a unique Raman signal. To detect either of these nanoparticles in animals, the investigators modified a standard Raman microscope to efficiently measure the Raman signal produced from deep inside living animals.
In one experiment, the investigators injected two different Nanoplex biotags into mice and were able to track both particles simultaneously as they moved through the animal. They subsequently repeated this experiment using four different biotags and again were able to track each of the particles based on their unique Raman signals. The researchers also showed that they could detect tumor-targeted SWCNTs at the sites of implanted tumors in live animals.