'NANOSTRUCTURED TIO2 AS A MULTIFUNCTIONAL MATERIAL: FROM PHOTOCATALYSIS TO BIOMEDICAL APPLICATIONS'

The results presented in this Ph.D. thesis are focused on the use of nanostructured titanium dioxide for environmental remediation and for biomedical applications. In the first part, the importance of the choice of a suitable and reliable synthetic route for obtaining nanomaterials with tailored properties for a specific application is highlighted. Several research projects on the design and sol-gel synthesis of TiO2 nanoparticles have been carried out. The experimental evidences suggest that sol-gel synthesis allow tailoring the morphological and superficial properties of the samples. The latter are strictly correlated to the photocatalytic activity of TiO2 home-made samples for the degradation of pollutants in air (e.g., toluene and nitrogen oxides). Moreover, exploiting the capability of sol-gel synthesis, the light absorption of the photocatalyst is extended from UV to the visible spectrum via a nitrogen doping. The morphology, bulk superficial properties, and photocatalytic activity of TiO2 nanoparticle are also influenced by the direct physical/chemical effects of ultrasounds. Interestingly, using ultrasonic spray pyrolysis (USP), we can exploit indirect effects of ultrasounds to synthesized nanostructured materials. Here, it is presented the design, synthesis, characterization, and application in photocatalysis of porous TiO2 microsphere with tunable physico-chemical properties obtained through USP. The second part of this Ph.D. thesis is focused on the study of the interaction among inorganic surfaces and biomolecules or, in general, biological systems. In a first work, we have synthesized sol-gel TiO2 nanoparticles with different morphology and use them for preliminary study of acetyl salicylic acid delivery. Moreover, the possibility to use TiO2 as a material for scaffold for bone regeneration is reported. This study has led to unravel a new bio-inspired crystallization pathway toward the bioactivity of synthetic bone substitutes. Other examples in the biomedical field are reported in Appendix A.