ИСТИНА

Unique properties of carbon nanomaterials, especially fullerenes and their solutions find increasingly wide acceptance in basic science and applied technologies. During the last decade, they are in demand in up-to-date energy systems and fine-chemical and drug synthesis. Recently, much attention has been paid to their use in medicine e.g. for drug delivery into cells or for attaching various substances to cell membrane surface. Here, one of the difficulties is the synthesis of non-toxic water-soluble fullerene compounds that can be introduced into human body. In this regard, of importance are aqueous dispersions of unmodified fullerenes (AFD). Nonetheless, AFDs show certain difficulties and often call for a chemical modification or the use of the toxic organic solvents. In addition, the aggregation properties of AFDs have not been studied in full. Thus, this hinders their use in medicine. The aim of this study is to develop approaches to the analysis of the fullerene aqueous dispersions and related materials. AFDs of C 60 and C 70 , and a technical mixture of C 60 and C were prepared according to the procedure of solvent-exchange protocol. Total organic carbon analyzer was used for developing the procedure for carbon total concentrations in AFDs. In addition, the content of fullerenes in their aqueous dispersions at a very low level (ppm) makes the use of classical methods of chemical analysis almost impossible. Thus, to solve this problem, low concentrations of fullerenes were determined using thermal-lens spectrometry. To prove the state of the unmodified fullerene in AFDs, their UV-visible absorption spectra as well as spectra of the toluene extracts were recorded; the data show that the majority of fullerene in AFDs is not chemically modified. In addition, MALDI confirmed the unmodified state of fullerenes in their AFD. An important parameter (because the cell membrane is able to pass a very limited size of the molecule clusters or aggregates into the cell) is the distribution of fullerene clusters size, which was implemented by DLS and PEM. As well, for the first time ultrasonic-assisted extraction of fullerenes from AFDs is reported, and the physicochemical parameters of this process are estimated. 70