Bezpečnostní aspekty nanomateriálů se zaměřením na fulleren C60

Abstract

Nanomaterials have found, due to their specific properties, their use not only in a wide range of technologies, but also in living systems. The study of fulleenes application is attractive and shows a clear potential of fulleren to recapture free radicals and reactive oxygen species. Due to this physico-chemical properties and the biological activity fullerene becomes a good candidate for use in the protection of persons against ionizing radiation, i.e. to act as a radioprotector. However, this use faced with the problem of a very low solubility of the hydrophobic carbon sphere itself in physiological media, accompanied by the formation of aggregates, so-called clusters. Dissolution process is the most common barrier for using yet known exploitable potential of fulleren. This question is dealt with derivatization by hydrophilic functional groups. This work provides the own laboratory available procedure of fullerene C60 hydroxylation by peracetic acid and solves imperative preparation of an aqueous solution of fullerene derivative (hereafter DF). Before testing of radioprotective properties it was with regard to the application in a biosystem tested the DF homogeneity and it was minimize the tendency to form clusters. For this purpose the microscopic analysis of DF (TEM, SEM), infrared spectroscopy (FTIR), electron diffraction analysis and NanoSight LM10HSB analysis (determination of the homogeneity and modal size of nanoparticles in solution) were performed. Toxicity tests of DF were performed (acute and prolonged) and the highest nontoxic concentration for a model organism fish Danio rerio (147 mg DF/l of water) was found. The protective ability of prepared DF against ionizing radiation has been demonstrated on a model organism at this nontoxic concentration of DF. LD50 of X rays increased to almost double for various intervals of survival from the time of irradiation. Survival LT50 increased by about 70%, depending on the applied doses (10-70 Gy). The proven effect is associated with the ability of DF to eliminate free radicals and oxidants resulting from radiolysis of water in biological systems. This property of prepared derivative is also applicable in another systems and materials for the persons protection (e.g. as the fire retarder, as the nanocomposit in nanofibres impacting their thermal properties and so on).