Cytotoxicity of Fullerenol C₆₀(OH)_22-24 to Human Peripheral Blood Monocytes

Fullerenol C₆₀(OH)_22-24 was tested for its effect on the viability of human peripheral blood monocytes, and its adhesion/internalization by monocytes was studied. Nanoparticles used at concentrations of 0.25, 0.5, 2.5, 5, 12.5, 25, 50, 100, and 200 μg/mL were incubated with human blood mononuclear cells for 24, 48, and 72 h (5% CO₂ at 37°C). Monocyte viability and fullerenol fluorescence intensity in the monocyte gate were then assessed by flow cytometry. Nanoparticles were adsorbed/internalized by cells in proportion to their concentration and incubation time. Fullerenol C₆₀(OH)_22-24 used at 200 μg/mL reduced the monocyte viability on average by 17, 30, and 28% after 24, 48, and 72 h, respectively. Cell survival inversely correlated with nanoparticle uptake intensity. The concentrations ≤100 μg/mL did not exhibit cytotoxicity even after prolonged exposure, supporting biomedical applicability of fullerenol.