Fullerenols are nanosized water-soluble polyhydroxylated derivatives of fullerenes, a specific allotropic form of carbon, bioactive compounds, and perspective basis for drug development. Our paper analyzes the antioxidant activity and toxicity of a series of fullerenols with different number of oxygen substituents. Two groups of fullerenols were under investigation: (1) C₆₀O_y(OH)_x, C_60,70O_y(OH)_x, where x+y = 24–28 and (2) C_60,70O_y(OH)_x, Fe_0,5C₆₀O_y(OH)_x, Gd@C₈₂O_y(OH)_x, where x+y = 40–42. Bioluminescent cellular and enzymatic assays (luminous marine bacteria and their enzymatic reactions, respectively) were applied to monitor toxicity in the model fullerenol solutions and bioluminescence was applied as a signaling physiological parameter. The inhibiting concentrations of the fullerenols were determined, revealing the fullerenols’ toxic effects. Antioxidant fullerenol’ ability was studied in solutions of model oxidizer, 1,4-benzoquinone, and detoxification coefficients of general and oxidative types (D_GT and D_OxT) were calculated. All fullerenols produced toxic effect at high concentrations (>0.01 g L⁻¹), while their antioxidant activity was demonstrated at low and ultralow concentrations (<0.001 g L⁻¹). Quantitative toxic and antioxidant characteristics of the fullerenols (effective concentrations, concentration ranges, D_GT, and D_OxT) were found to depend on the number of oxygen substituents. Lower toxicity and higher antioxidant activity were determined in solutions of fullerenols with fewer oxygen substituents (x+y = 24–28). The differences in fullerenol properties were attributed to their catalytic activity due to reversible electron acceptance, radical trapping, and balance of reactive oxygen species in aqueous solutions. The results provide pharmaceutical sciences with a basis for selection of carbon nanoparticles with appropriate toxic and antioxidant characteristics. Based on the results, we recommend, to reduce the toxicity of prospective endohedral gadolinium-fullerenol preparations Gd@C₈₂O_y(OH)_x, decreasing the number of oxygen groups to x+y = 24–28. The potential of bioluminescence methods to compare toxic and antioxidant characteristics of carbon nanostructures were demonstrated.

The technique of some nanosized substances synthesis in arc discharge plasma at atmospheric pressure is considered. The results of synthesis in the arc discharge with different feeding are presented: dc, power current of 50 Hz, ac of 44 kHz and their combinations. Also, the investigation results of influence of an acoustic field and a co‐phased magnetic field on fullerene synthesis at atmospheric pressure are presented.

Fullerene is a nanosized carbon structure with potential drug delivery applications. We studied the bioeffects of a water-soluble fullerene derivative, fullerenol, with 10-12 oxygen groups (F10-12); its structure was characterized by IR and XPS spectroscopy. A bioluminescent enzyme system was used to study toxic and antioxidant effects of F10-12 at the enzymatic level. Antioxidant characteristics of F10-12 were revealed in model solutions of organic and inorganic oxidizers. Low-concentration activation of bioluminescence was validated statistically in oxidizer solutions. Toxic and antioxidant characteristics of F10-12 were compared to those of homologous fullerenols with a higher number of oxygen groups:F24-28 and F40-42. No simple dependency was found between the toxic/antioxidant characteristics and the number of oxygen groups on the fullerene’s carbon cage. Lower toxicity and higher antioxidant activity of F24-28 were identified and presumptively attributed to its higher solubility. An active role of reactive oxygen species (ROS) in the bioeffects of F10-12 was demonstrated. Correlations between toxic/antioxidant characteristics of F10-12 and ROS content were evaluated. Toxic and antioxidant effects were related to the decrease in ROS content in the enzyme solutions. Our results reveal a complexity of ROS effects in the enzymatic assay system.

Fullerenols are nanosized water-soluble polyhydroxylated derivatives of fullerenes, specific allotropic form of carbon, bioactive compounds and perspective pharmaceutical agents. Antioxidant activity of fullerenols was studied in model solutions of organic and inorganic toxicants of oxidative type - 1,4-benzoquinone and potassium ferricyanide. Two fullerenol preparations were tested: С60О2-4(ОН)20-24 and mixture of two types of fullerenols С60О2-4(ОН)20-24+С70О2-4(ОН)20-24. Bacteria-based and enzyme-based bioluminescent assays were used to evaluate a decrease in cellular and biochemical toxicities, respectively. Additionally, the enzyme-based assay was used for the direct monitoring of efficiency of the oxidative enzymatic processes. The bacteria-based and enzyme-based assays showed similar peculiarities of the detoxification processes: (1) ultralow concentrations of fullerenols were active (ca 10-17-10-4 and 10-17-10-5 g/L, respectively), (2) no monotonic dependence of detoxification efficiency on fullerenol concentrations was observed, and (3) detoxification of organic oxidizer solutions was more effective than that of the inorganic oxidizer. The antioxidant effect of highly diluted fullerenol solutions on bacterial cells was attributed to hormesis phenomenon; the detoxification was concerned with stimulation of adaptive cellular response under low-dose exposures. Sequence analysis of 16S ribosomal RNA was carried out; it did not reveal mutations in bacterial DNA. The suggestion was made that hydrophobic membrane-dependent processes are involved to the detoxifying mechanism. Catalytic activity of fullerenol (10-8 g/L) in NADH-dependent enzymatic reactions was demonstrated and supposed to contribute to adaptive bacterial response.