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.

Recent progress in nanobiotechnology has attracted interest to a biomedical application of the carbon nanostructure C60 fullerene since it possesses a unique structure and versatile biological activity. C60 fullerene potential application in the frame of cancer photodynamic therapy (PDT) relies on rapid development of new light sources as well as on better understanding of the fullerene interaction with cells. The aim of this study was to analyze C60 fullerene effects on human leukemic cells (CCRF-CEM) in combination with high power single chip light-emitting diodes (LEDs) light irradiation of different wavelengths: ultraviolet (UV, 365 nm), violet (405 nm), green (515 nm) and red (632 nm). The time-dependent accumulation of fullerene C60 in CCRF-CEM cells up to 250 ng/106 cells at 24 h with predominant localization within mitochondria was demonstrated with immunocytochemical staining and liquid chromatography mass spectrometry. In a cell viability assay we studied photoexcitation of the accumulated C60 nanostructures with ultraviolet or violet LEDs and could prove that significant phototoxic effects did arise. A less pronounced C60 fullerene phototoxic effect was observed after irradiation with green, and no effect was detected with red light. A C60 fullerene photoactivation with violet light induced substantial ROS generation and apoptotic cell death, confirmed by caspase3/7 activation and plasma membrane phosphatidylserine externalization. Our work proved C60 fullerene ability to induce apoptosis of leukemic cells after photoexcitation with high power single chip 405 nm LED as a light source. This underlined the potential for application of C60 nanostructure as a photosensitizer for anticancer therapy.

Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To ad

A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle—C₆₀ fullerene (C₆₀)—for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C₆₀-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV–Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C₆₀ molecule. The computer simulation showed that π-stacking dominates in Ber and C₆₀ binding in an aqueous solution. Complexation with C₆₀ was found to promote Ber intracellular uptake. By increasing C₆₀ concentration, the C₆₀-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C₆₀-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C₆₀ improved its in vitro efficiency against cancer cells.

A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C₆₀ fullerene (C₆₀) were applied in 1:1 and 2:1 molar ratio, exploiting C₆₀ both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox’s nuclear and C₆₀’s extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox’s antiproliferative activity and C₆₀’s photoinduced pro-oxidant activity. When cells were treated with 2:1 C₆₀-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C₆₀-Dox enabled a nanomolar concentration of Dox and C₆₀ to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC₅₀ 16, 9 and 7 × 10³-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C₆₀’s photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C₆₀-mediated Dox delivery and C₆₀ photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C₆₀-Dox nanoformulation provides a promising synergetic approach for cancer treatment.