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Friday, September 28, 2007

Safer Light-Activated Nanoparticle Cancer Therapy

Oncologists have long suspected that photodynamic therapy could find broader use if only there was some way to limit the accumulation of photosensitizer molecules to tumors, sparing healthy tissue from unintended damage. Now, using modified silica nanoparticles, a team of investigators at the State University of New York, Buffalo, has developed a photosensitizer delivery method that has the potential to target tumor cells specifically.

His group has used porous silica nanoparticles modified in such a way as to form a strong chemical bond between the nanoparticles and the photosensitizer molecules. When exposed to light, the permanently entrapped photosensitizer still produces reactive oxygen molecules that can diffuse out of the nanoparticles through their porous silica shells.

The investigators found, too, that human colon cancer cells readily take up the photosensitizer-loaded nanoparticles. More importantly, shining light on these cells resulted in their death.