Organically Modified Silica Nanoparticles with Intraparticle Heavy-Atom Effect on the Encapsulated Photosensitizer for Enhanced Efficacy of Photodynamic Therapy.

We report a novel nanoassembly formulation for photodynamic therapy, which is composed of covalently iodine-concentrated organically modified silica (ORMOSIL) nanoparticles (diameter <30 nm) and a hydrophobic photosensitizer embedded therein. Comparative studies with iodinated and non-iodinated nanoparticles have demonstrated that the intraparticle external heavy-atom effect on the encapsulated photosensitizer molecules significantly enhances the efficiency of 1O2 generation, and thereby, the in vitro PDT efficacy.