Endohedral Gd-Containing Fullerenol: Toxicity, Antioxidant Activity, and Regulation of Reactive Oxygen Species in Cellular and Enzymatic Systems

The Gd-containing metallofullerene derivatives are perspective magnetic resonance imaging contrast agents. We studied the bioeffects of a water-soluble fullerene derivative, gadolinium-endohedral fullerenol, with 40–42 oxygen groups (Gd@Fln). Bioluminescent cellular and enzymatic assays were applied to monitor toxicity and antioxidant activity of Gd@Fln in model solutions; bioluminescence was applied as a signaling physiological parameter. The Gd@Fln inhibited bioluminescence at high concentrations (>2·10−1 gL−1), revealing lower toxicity as compared to the previously studied fullerenols. Efficient activation of bioluminescence (up to almost 100%) and consumption of reactive oxygen species (ROS) in bacterial suspension were observed under low-concentration exposure to Gd@Fln (10−3–2·10−1 gL−1). Antioxidant capability of Gd@Fln was studied under conditions of model oxidative stress (i.e., solutions of model organic and inorganic oxidizers); antioxidant coefficients of Gd@Fln were determined at different concentrations and times of exposure. Contents of ROS were evaluated and correlations with toxicity/antioxidant coefficients were determined. The bioeffects of Gd@Fln were explained by hydrophobic interactions, electron affinity, and disturbing of ROS balance in the bioluminescence systems. The results contribute to understanding the molecular mechanism of “hormetic” cellular responses. Advantages of the bioluminescence assays to compare bioeffects of fullerenols based on their structural characteristics were demonstrated

Obtaining of hydroxylated fullerenes Y@C82OX(OH)Y, Y2@C82OX(OH)Y, Y2C2@C82OX(OH)Y and electrophysical characteristic of composite film based thereon

The article presents, for the first time, the results of the research on composite film obtained from hydroxylated endohedral metallofullerenes (EMF) Y@C82, Y2@C82, with Y2C2@C82 and highest fullerenes as dopant. The composite film has been established to have electric conductivity and to be a ferroelectric with the value of residual polarization of ~0.75 mkC/cm2. The impedance spectroscopy of this sample allowed us to determine dispersion of dielectric permittivity and conductivity in the range of frequencies of 0.5Hz–100MHz. It is stated that the value of the high-frequency dielectric permittivity of films is e' = 2.8. However, with reduction in the electric field frequency, real and imaginary parts of e increase to values ~10^4–10^5. Such increase in dielectric permittivity is connected with increase in polarizing caused by accumulation of mobile electric charges (electrons of ions, protons) on boundaries of the structural defects of a film, which are divided by thin dielectric interlayers. The film is solid electrolyte with the ionic conductivity of ~5*10^(-7) S/cm

Ultrafast method of fullerenes extraction from carbon condensate

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The Soxhlet extraction method (SE) only used in the extraction of fullerenes from carbon condensate (CC) obtained in the fullerene production facility, which in the literature is often referred to as carbon black, does not provide complete extraction. Fullerenes can also be extracted from the CC suspension and the solvent by the mechanical extraction method (ME) and show higher degree of extraction efficiency. This method combined with filtration process takes only a few minutes and allows a significant reduction in solvent consumption. Extraction via the ME method application makes it possible to carry out extraction of fullerenes twenty times faster than by the SE method. It can be used as an independent method, bypassing the extraction by the SE method, and also as an additional one. Application of the ME method allows additional extraction of fullerenes weight percentage from the CC, after extracting fullerenes from it applying the SE method. In this instance the higher fullerenes prevail in the essences extracted by the ME method with their content reaching as high as 39.50wt%. The obtained samples of fullerene mixtures (FM) are characterized by the methods of high-performance liquid chromatography and mass spectrometry. Analysis of the results shows that the composition of the FM, isolated by the ME method, differs from the compositions extracted via the SE method

Analysis of Geological Samples by Method of Emission Spectroscopy using Setup ISSP-1

В работе представлены результаты атомно-эмиссионного анализа геологических проб, полученные при использовании установки ИССП-1. Выполнен количественный анализ донных осадков и проб, содержащих капсулированное золото.The emission analysis results of geological samples which were received using setup ИССП-1 were presented. Quantitative analysis of seafloor deposits and samples contained encapsulated aurum was carried out

Filtration process combined with mechanical action, as a method for efficient extraction of endohedral metallofullerenes from carbon soot

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The paper presents results of fullerenes and endohedral metallofullerenes extracts studies, isolated from the graphite rods carbon soot spray, and containing Y2O3 in a high frequency arc discharge. Two ways of extraction were applied and compared – (1) the classic method of Soxhlet extraction, and (2) the one developed by our team – extraction based on mechanical action combined with filtration. To implement the method, we used a laboratory version of installation, embodying technical solutions for rapid extraction. Chromatographic and mass spectrometry studies of fullerene extracts obtained by these methods revealed that by combining mechanical action with simultaneous filtration, we can significantly intensify and reduce the process of extracting fullerenes and endohedral metallofullerenes compared to the Soxhlet extraction method. This is especially evident in the release of endohedral metallofullerenes. Our method allows to reduce the release time of fullerenes from 10 g of carbon soot on laboratory installation up to 15 minutes, against the Soxhlet extraction method taking 18 hours. Whilst, the total number of fullerenes extracted by both methods almost coincides (the extraction method using mechanical action allowed us to extract 0.2-0.4 wt. % more), the composition of the isolated fullerene mixtures is different. The relative content of higher fullerenes and endohedral metallofullerenes exceeds when the mechanical action-based extraction method applied

Analysis of Geological Samples by Method of Emission Spectroscopy using Setup ISSP-1

В работе представлены результаты атомно-эмиссионного анализа геологических проб, полученные при использовании установки ИССП-1. Выполнен количественный анализ донных осадков и проб, содержащих капсулированное золото.The emission analysis results of geological samples which were received using setup ИССП-1 were presented. Quantitative analysis of seafloor deposits and samples contained encapsulated aurum was carried out

Antioxidant Activity and Toxicity of Fullerenols via Bioluminescence Signaling: Role of Oxygen Substituents

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) C60Oy(OH)x, C60,70Oy(OH)x, where x+y = 24–28 and (2) C60,70Oy(OH)x, Fe0,5C60Oy(OH)x, Gd@C82Oy(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 (DGT and DOxT) 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, DGT, and DOxT) 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@C82Oy(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

Application Perspectives of Nanocomposites Based on Carbon, Containing Mg, Ni, Ti as Materials for Hydrogen Storage

Выполнено экспериментальное исследование каталитической активности переходных металлов Ti и Ni для процессов гидрирования/дегидрирования Mg. Методом плазмохимического синтеза были получены нанокомпозиты, стабилизированные углеродом, со следующими составами: Mg-C, Mg-Ti-C, Mg-Ni-C. Гидрирование нанокомпозитов осуществлялось как в процессе синтеза, так и под давлением (6 МПа) в течение 20 мин. Процесс дегидрирования производился путем нагрева до 700 °С со скоростью 1 °С/с. У нанокомпозитов, гидрированных в процессе синтеза, образование гидрида магния произошло только в композите Mg-Ni-C. Разложение данного гидрида осуществлялось при температуре 644 °С. У нанокомпозитов, гидрированных под давлением, температура начала разложения гидрида магния в композите Mg-Ni-C составила 300 °С , в Mg-Ti-C – 450 °С. Таким образом, нанокомпозит Mg-Ni-C создает наилучшие условия для гидрирования/дегидрирования водорода.The catalytic activity experimental study of the transition metals Ti and Ni for hydrogenation/ dehydrogenation of Mg was carried out. By plasma-chemical synthesis the nanocomposites stabled by carbon were obtained. They had the following composition: Mg-C, Mg-Ti-C, Mg-Ni-C. The nanocomposites hydrogenation was carried out both in the process of synthesis and under pressure (6 MPa) for 20 minutes. Dehydrogenation process was fulfilled by heating to 700 °С at a rate of 1 °С/s. Magnesium hydride formation occurred only in the composite of Mg-Ni-C for nanocomposites which were hydrotreated under synthesis. The decomposition of this hydride was took place under the 644 °С. In case of nanocomposites, hydrogenated under pressure, the magnesium hydride decomposition start temperature in the Mg-Ni-C was 300 °С, in the Mg-Ti-C – 450 °С. Thus, the nanocomposite Mg-Ni-C provides the best conditions for the hydrogenation / dehydrogenation of hydrogen