Hematoporphyrin IX can generate reactive oxygen species (ROS) upon irradiation, which are used against tumors in photodynamic therapy (PDT). Clinically, dosing is difficult and adverse reactions can occur. By conjugating the porphyrin with SiO2 nanospheres, its dosage and the release of ROS can be better controlled. Silica has the advantage of easy surface functionalization for targeting. Hp IX SiO2 nanoparticles have been functionalized with amine-groups.  This project sought to determine the change in properties (surface charge, fluorescence quenching and singlet oxygen generation) when the surface groups were changed to thiol, carboxylate and imidazolinium. Hp IX incorporated in silica nanospheres interacted with Fe2+ (fluorescence quenching) and was protected from interaction with Br-. The singlet oxygen efficiency was reduced compared to free Hp IX, but the reduction in efficiency could be countered by the improved selectivity of functional groups. Cellular tests are necessary to determine the effects of functional groups on PDT.

Effects of surface functionalization on the characteristics of Hp IX-containing SiO<sub>2</sub> nanoparticles

243rd National Meeting (2012)

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Effects of surface functionalization on the characteristics of Hp IX-containing SiO2 nanoparticles

Effects of surface functionalization on the characteristics of Hp IX-containing SiO₂ nanoparticles