Effect of LaF3: Ag fluorescent nanoparticles on photodynamic efficiency and cytotoxicity of Protoporphyrin IX photosensitizer.

LaF3: Ag nanoparticles (NPs) were synthesized by the co-precipitation method. The produced NPs were characterized by X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The emission spectrum of LaF3:Ag NPs is mostly overlapped with the absorption band of protoporphyrin IX (PpIX) and their conjugation was confirmed by studying fluorescence resonance energy transfer (FRET) from LaF3:Ag donor to protoporphyrin IX acceptor. The energy transfers from LaF3:Ag NPs to photosensitizer molecules is very efficient. So, the produced LaF3:Ag NPs can be recommended as light source for photodynamic therapy (PDT). The thiol group of cysteine was bound to LaF3:Ag NPs in order to conjugate LaF3:Ag NPs and protoporphyrin IX. UVC light source was used to excite fluorescent LaF3:Ag NPs. The reactive oxygen species (ROS) produced by photosensitizer was identified using special fluorescent probes (anthracene, methylene blue and methyl orange) as detectors.