Síntese e caracterização de fulerenos e fulerois visando aplicações biológicas

Abstract

In this work, we studied the synthesis of fullerenes by the voltaic arc method. Different purification techniques were also developed, such as humid (Soxhlet) and physical separation (sublimation). Produced fullerenes were characterized by spectroscopic techniques, with emphasis in infrared spectroscopy. In the second phase of this work, a new chemical route to functionalize fullerenes was developed, with the objective of producing fulleróis, fullerenes molecules containing 18 to 20hydroxyl groups (-OH) covalently bonded. These are water soluble molecules, a primary property required to develop biological applications. To characterize the atomic structure and optical properties of these new molecules, a vast array of spectroscopic techniques was employed.Two possible fullerol applications in biology were also studied in this work. The first was motivated by the fullerenes and its derivatives ability to generate reactive oxygen species (ROS) when under illumination. An in vitro study of the cells viability was conducted with Candida krusei yeast colonies, when under monochromatic illumination in the presence of fulleróis. Results showed that the fullerol can be used as a photosensitizer in photodynamic therapies (PDT) when illuminated with UVA radiation (l ~ 366 nm) and, also, in the studied concentrations and in the absence of light, these molecules did not present any citotoxicity. The second application investigated makes use of the fullerols properties as a free radical trap. In vivo ischemia/reperfusion studies in mice were made, to assert the antiinflammatory effect of fulleróis, which is probably due to free radical trapping.