Gold Nanoparticle-Enhanced Photodynamic Therapy from Photosensitiser-Entrapped Ormosil Nanoparticles

Herein, we investigate the effect of the surface attachment of gold nanoparticles (AuNPs) on photosensitiser-entrapped organically modified silica (ormosil) nanoparticles for enhanced photodynamic therapy (PDT). Photosensitiser methylene blue (MB)-entrapped ormosil nanoparticles of three different diameters (30/55/80 nm) were synthesised, and AuNPs were attached to their surface. Subsequent light irradiation with a 630 nm laser resulted in the production of singlet oxygen (1O2), with different amounts depending on the diameter of the ormosil nanoparticle. Enhancement in 1O2 production was observed upon the AuNP attachment on the ormosil surface. In vitro studies in pancreatic cancer (Panc-1) cells have demonstrated that cellular uptake and photodynamic cytotoxicity are also dependent on the size of ormosil nanoparticles and AuNP attachment. These studies pave the way for designing ormosil nanoparticles with suitable size and surface attachment for PDT applications.