Researchers from the University of Hull have discovered a way to load up nanoparticles with large numbers of light-sensitive molecules to create a more effective form of photodynamic therapy (PDT) for treating cancer.

The nanoparticles were designed to be the perfect size and shape to penetrate easily into a tumor, the researchers said.

Most PDT works with individual light-sensitive molecules, but the new nanoparticles could each carry hundreds of molecules to a cancer site. The nanoparticles were made from a material that limits the leaching of its contents while in the bloodstream ujtil activated with light at a tumor site, causing toxic reactive oxygen to diffuse freely out of the particles. Cellular damage is confined to the area of the cancer.

The researchers tested the nanoparticles on colon cancer cells. They found that the nanoparticles were also effective near (rather than inside) the cancer cells.

“Some types of cancer cell are able to expel conventional drugs, so if we can make this kind of therapy work simply by getting the nanoparticles between the cancer cells, rather than inside them, it could be very beneficial,” said Dr. Ross Boyle.

Ref.: Ross W. Boyle, et al., Polyacrylamide Nanoparticles as a Delivery System in Photodynamic Therapy, Molecular Pharmaceutics, 2011; 110316145246004 [DOI: 10.1021/mp200023y]