Fabrication and Study of Organic Nanomaterials as Photosensitizers for Photodynamic Therapy

During the last decade, organic nanomaterials have emerged as an exciting research area due to their chemical, magnetic, and optical properties. In biomedicine, the possibility of the nanomaterials to produce reactive oxygen species (ROS) and their luminescence properties are used for the diagnostic and treatment of some specific diseases. Photodynamic therapy (PDT) is an unintrusive procedure that involves the photoactivation, with a specific wavelength, of a photosensitizer (PS) to produce ROS, especially singlet oxygen, which is the responsible for provoking damage to precise cells; however, its performance would increase if we developed the photosensitizers as nanoparticles. In this work, we reported the study and fabrication of silica core-shell nanoparticles (SNP). These nanomaterials were manufactured by a microemulsion method using an inert or photoluminescent polymer as a core. The surface of the nanoparticle was functionalized with Thionine colorant, which was previously tested as a photogenerator of ROS. The optical and morphological properties of nanoparticles were evaluated by UV-Vis spectroscopy, photoluminescence, and scanning electron microscopy (SEM). Finally, the generation of singlet oxygen was evaluated using an indirect test, by using as an excitation source, a green laser (532 nm). The results indicate that the photoluminescent SNPs generate singlet oxygen so they could be considered as a PS.