Zinc TetraPhenylPorphyrin / Dextran-Graft-PolyAcrylAmide / Gold Nanoparticles Hybrid Nanosystem for Photodynamic Therapy: Plasmonic Enhancement Effect

In recent years, great attention towards alternative antitumor and antibacterial therapies such as antibacterial photodynamic therapy (PDT) has been raised. The development of nanotechnology has opened wide opportunities for the creation of new multifunctional hybrid multicomponent nanosystems with high potential for PDT applications. In particular, those are the Photosensitizer / Polymer / Metal nanoparticles nanosystems containing the photosensitizer as a drug, polymer as a drug nanocarrier, and metal nanoparticles as an enhancer of drug efficiency. The Zinc TetraPhenylPorphyrin photosensitizer / Dextran-graft-PolyAcrylAmide copolymer / Au NanoParticles (ZnTPP/D-g-PAA/AuNPs) triple hybrid nanosystem were synthesized in water solution as a nanodrug for potential use in PDT applications. Dynamic light scattering has proved the aggregation and sedimentation stability of this system during several days after preparation. The absorption and fluorescence spectra of ZnTPP/D-g-PAA/AuNPs water solution have proved the binding of ZnTPP molecules with both D-g-PAA and D-g-PAA/AuNPs macromolecules.  The gold concentration of 0.005 mg/mL was shown to be optimal providing the highest plasmonic enhancement of the electronic processes involving the ZnTPP photosensitizer. The 3.2 times enhancement of singlet oxygen photogeneration under resonant with localized surface plasmon wavelength excitation has been detected for ZnTPP/D-g-PAA/AuNPs that proves the plasmonic origin of such phenomenon. The high bactericidal efficiency of ZnTPP/D-g-PAA/AuNPs water solution at 530 nm light irradiation was revealed for wild strains of Staphylococcus aureus.  These data indicate that ZnTPP/D-g-PAA/AuNPs hybrid nanosystem is quite promising for rapid antibacterial photodynamic therapy, the open wounds in particular.