Aplicação de técnicas fototérmicas no estudo de biomateriais

Abstract

In this work photothermal and conventional techniques were employed to study biomaterials. The photoacoustic spectroscopy technique was used to evaluate the penetration rate of a phyto-pharmaco, a sunscreen, and an infusion topically applied onto skin and oral mucosa surfaces. As the phyto-pharmaco effectiveness depends on its penetration throughout the skin up to the dermis, it was necessary to perform a depth profile analysis in order to monitor the behavior of the mentioned formulation over the skin as a function of time interval of treatment. Photoacoustic spectroscopy was also applied to evaluate the action of an infusion popularly known to be effective in the treatment of dentoalveolar inflammatory processes. An additional study of the penetration rate of the infusion was performed to investigate its expected action. The third study with this technique was the characterization of an extract obtained from a phyto-pharmaco and its fractions that presented properties of sunscreens against UV radiation. The analysis of the optical transmission and absorption spectra of these substances suggested that they may be suitable for photoprotection against UVB and UVA radiation. The formulation characteristics and penetration rate throughout the skin were evaluated in "ex vivo" experiments in rats. In the second phase of the work, the thermo-optical properties of oils heated and reused for frying were measured using photothermal, calorimetric, interferometric and mass density methods. The focus of the study was the evaluation of factors that can contribute both to define limits to reuse these oils and to differentiate types of oils. A final study was perfomed with the photoacoustic spectroscopy to verify the ability of the β-ciclodextrin to remove cholesterol from butter. The results of this work showed once again that the photothermal techniques are technological tools that can be helpful in the quality control of medicaments and foods in natura and industrialized. The validation of these studies with further application in other systems may result in the establishment of novel indexes to be used in the certification of biomaterials used by the population.