Fluorescent superparamagnetic magnetite-silica nanocomposites as carriers of a platinum diimine complex for photodynamic therapy.

Novel fluorescent superparamagnetic nanocomposites have been fabricated by introduction of the coumarin group on the surface of amine-functionalized magnetite-silica nanocomposites, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, fluorescence spectra, dynamic light scattering and vibrating sample magnetometer techniques. The nanocomposites were employed as delivery vehicles of a photoactive platinum diimine complex. The cellular uptake and photocytotoxicity of the photosensitizer-loaded nanocomposites in HeLa cells (human cervical cancer line) or HL-7702 cells (human liver cell line) have been studied by fluorescence spectra and cell viability assay, respectively. The results suggest that the nanocomposites can be used to monitor the cellular uptake of the photosensitizer, and can significantly enhance the photocytotoxicity of the photosensitizer towards cancer cells when employed as carriers of the photosensitizer. Also, the photosensitizer-loaded nanocomposites are almost nontoxic to human normal cells either in the dark or after irradiation.