A novel formulation of chitosan nanoparticles functionalized with titanium dioxide nanoparticles

Herein, chitosan nanoparticles (CS-NPs) were prepared and functionalized chemically with titanium dioxide nanoparticles (TiO₂-NPs) to allow on-demand degradation of CS-NPs, using ultraviolet (UV) irradiation as a trigger. This is expected to allow drug release depending on patients' needs or physiological circumstances. Eleven formulations were arranged and their particle size, charge, and polydispersity were determined. The effect of CS-NPs size and the amount of TiO₂-NPs, on the system collapse, was studied accordingly. Moreover, the collapse of these systems was examined using a fluorescence microscope after loading CS-NPs with Rhodamine. The formulations showed high monodispersity and had sizes ranged between 170 and 440 nm and charges ranged between +5 and +34 mV. Scanning electron microscope, Fourier-transform infrared spectroscopy, and X-ray diffraction proved the chemical deposition of TiO₂-NPs on CS-NPs. The dye test showed that there are two factors that oppose each other and affected the deposition of TiO₂-NPs on CS-NPs, the size of CS-NPs, and the amount of TiO₂-NPs used. In addition, the dye test showed that the deposition of TiO₂-NPs is a saturated process that relies on the amount of TiO₂-NPs used initially. Finally, the intensity of Rhodamine released from these systems after illumination with UV light was related to the amount of TiO₂-NPs deposited on CS-NPs. In conclusion, functionalization of CS-NPs with TiO₂-NPs can be controlled and used to rupture CS-NPs on demand by illumination with UV light.