The method of preparation of highly stable reproducible C₆₀ fullerene aqueous colloid solution is described. The structural organization of C₆₀ fullerenes in aqueous solution was studied and analyzed in detail using various techniques such as chemical analysis, UV/VIS spectroscopy, atomic force and scanning tunneling microscopy, dynamic light scattering, and zeta potential methods.

Toxicity of the C₆₀ fullerene aqueous colloid solution in vitro and in vivo experiments was studied. C₆₀ fullerene in the concentration range of 3.6-144 µg/mL demonstrated low toxicity against human embryonic kidney (HEK293) cells with 383.4 μg/mL IC₅₀ value. The acute toxicity of C₆₀ fullerene in a dose progression (75, 150, 300, 600, 1200 and 1800 mg/kg) was investigated at 14^th day after single intraperitoneal (i.p.) administration into mice. No toxic effect of С₆₀ fullerene in the dose range of 75-150 mg/kg was observed; the calculated LD₅₀ value was 721 mg/kg. The toxic effect of C₆₀ fullerene was observed at a concentration of 300 mg/kg and higher, it was accompanied with mice behavior disturbance, hematotoxicity and pathomorphological changes in spleen, hepatic and kidney tissues. In mice treated with 600 mg/kg of C₆₀ fullerene indices of inflammatory process were detected, whereas at 1200 mg/kg dose leukopoies and thrombocytopoies were found to be suppressed. Thus, C₆₀ fullerene aqueous colloid solution in a dose range of 75-150 mg/kg is nontoxic and could be used for biomedical purposes.