Arquiteturas porosas à base de sílica como plataformas para encapsulamento de ftalocianinas: uma abordagem versátil para aplicações fotoquímicas avançadas

Abstract

Development of functionalized nanomaterials with photoactive properties has attracted growing interest in fields such as medical therapies and environmental technologies. In this work, porous silica-based core–shell architectures were prepared, in which the core consists of magnetite and the shell of mesoporous silica, employed as platforms for the encapsulation of zinc phthalocyanine (ZnPc), a photosensitizer with recognized efficiency in singlet oxygen generation under visible light irradiation. Immobilization of ZnPc in the silica matrix pores aims to enhance its stability in aqueous and biological media, while preserving its photodynamic activity by minimizing molecular aggregation that reduces the quantum efficiency of the free material. The nanoparticles and photosensitizer obtained were characterized by ELEMENTAL ANALYSIS (CHN), X-RAY FLUORESCENCE (WDXRF), SCANNING ELECTRON MICROSCOPY/ENERGY-DISPERSIVE X-RAY SPECTROSCOPY (SEM/EDS), XRAY DIFFRACTION (XRD), FOURIER-TRANSFORM INFRARED SPECTROSCOPY (FTIR), RAMAN SPECTROSCOPY, UV–VIS SPECTROSCOPY and FLUORESCENCE EMISSION SPECTROSCOPY, as well as by direct and indirect methods for singlet oxygen characterization, confirming functionalization, encapsulation and the optical, structural and elemental properties of the system. Preliminary assays evaluated the efficiency of the materials in two contexts: singlet oxygen generation for photodynamic therapy (PDT) and photodegradation of organic dyes as a model for the treatment of recalcitrant effluents. The results indicate that silica-based core–shell architectures (Fe3O4@SiO2) functionalized with ZnPc represent a promising approach, combining structural stability, photosensitizing efficiency and multifunctional potential for advanced photochemical applications in biomedical and environmental contexts.