Polyelectrolyte wrapped methylation morpholine-phthalocyanine@gold nanorod for synergistic photodynamic therapy and photothermal therapy photodegradation of DNA

It has been demonstrated that the synergistic photodynamic therapy and photothermal therapy offer a great therapeutic potential, although more research need to be exploit before this approach could be implemented. We investigated the synergistic effect of water soluble morpholine methylated phthalocyanine loaded on the surface of multilayer polyelectrolyte-coated gold nanorods for photodegradation of DNA. Two morpholine substituted zinc(II)/silicon(IV) phthalocyanines and their corresponding methylation water soluble cationic complexes were synthesized. The photophysical properties of two phthalocyanines were compared by UV/Vis, fluorescence spectroscopy and cyclic voltammetry methods. Tetra-[N-(methyliodide-morpholinyl)ethoxy] zinc(II) phthalocyanine (MLZnPcI4) was loaded into the multilayer polyelectrolyte-coated gold nanorods to form AuNR-PSS-MLZnPcI4 nanoparticles through electrostatic interaction. The nanoparticle was characterized by transmission electron microscope (TEM), atomic force microscope (AFM) as well as electronic differential system (EDS). The photophysical/photochemical properties of nanoparticles were studied. After being loaded on the gold nanorods, the fluorescence intensity, fluorescence quantum yield of MLZnPcI4 decreased. Upon irradiated by laser, MLZnPcI4 was released from nanoparticles due to the gold nanorods absorbed light energy and transformed it into heat and simultaneously produce 1O2, AuNR-PSS-MLZnPcI4 could effectively photodegrade DNA through synergistic photodynamic and photothermal therapy effect.