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Posted: Jan 19, 2012
Bismuth nanoparticles provide high fidelity images of breast tumors
(Nanowerk News) By combining a nanoparticle that is readily visible in X-ray computed tomography (CT) scans with a molecule that targets tumor lymph vessels and other tumor tissues, a research team from the University of California, San Diego (UCSD) and the Sanford-Burnham Medical Research Institute has developed a new imaging agent that provides high-fidelity CT images of tumors and their edges.
The researchers chose to create a nanoparticle from bismuth, the same element that forms the active ingredient in Pepto-Bismol. Bismuth, with its relatively large and massive nucleus, interacts strongly with X-rays, making it an ideal agent to increase contrast in CT images. To target their bismuth nanoparticles to tumors, the investigators used a small cyclic peptide known as LyP-1. This peptide, discovered in Dr. Ruoslahti's laboratory, homes specifically to the lymphatic vessels that drain many tumors, as well as to tumor tissues themselves.
Safety tests showed that the bismuth-LyP-1 nanoparticle was well-tolerated when injected into mice and that the nanoparticles cleared from blood and accumulated in tumors within 24 hours. CT imaging of tumor-bearing mice clearly revealed the presence of tumors and provided a very sharply-detailed image of the tumor margins for a full week after injection. Eventually, the nanoparticles clear from the body through the intestines.