Effect of Fullerenol C₆₀(OH)₂₄ on the Viability and Metabolism of THP-1 Cells

Fullerenols are polyhydroxylated derivatives of fullerene (C₆₀(OH)_n) with antioxidant, antiviral, and antibacterial properties and potential biomedical applications due to their solubility and biocompatibility. However, comprehensive assessment of their cytotoxicity is required, particularly regarding their effects on immune system cells. This study investigated the effects of fullerenol C₆₀(OH)₂₄ (MST-Nano, St. Petersburg, Russia) on the viability, apoptosis, and metabolism of THP-1 human monocytic leukemia cells. Cells were treated with concentrations ranging from 0.25 to 1000 µg/mL and incubated for 24, 48, and 72 h. Viability, apoptosis, and nanoparticle association were assessed by flow cytometry; glycolysis and mitochondrial respiration were measured after 24 h on a Seahorse XFe96 analyzer (Agilent Technologies, Santa Clara, CA, USA). Results showed that the effects of fullerenol depend on concentration and exposure time. At 24 h, 750 µg/mL increased viability, while 1000 µg/mL induced apoptosis. After 48 and 72 h, apoptosis increased at concentrations ≥750 µg/mL, with reduced viability. Nanoparticle association correlated with concentration and inversely correlated with viability but was independent of incubation time. Metabolic analysis revealed decreased glycolysis at 750 µg/mL after 24 h, while mitochondrial respiration was unaffected. Thus, our study demonstrated that fullerenol nanoparticles were safe for the THP-1 monocytic cell line up to 500 µg/mL.