Visible Light Irradiation of [60]Fullerene Causes Killing and Initiation of Transformation in Balb/3T3 Cells

Abstract

Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C₆₀) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C₆₀ was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C₆₀ was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C₆₀ and light, but it was equivocal in the standard two-stage transformation assay.     

The Effects of Fullernes on the Initiation and Promotion Stages of Balb/3t3 Cell Transformation

Fullerene C₆₀ and a mixture of fullerenes C₆₀ and C₇₀ were solubilized in a culture medium with poly(vinylpyrrolidone) and examined for the effects on two-stage cell transformation in vitro, a model of carcinogenesis. They showed neither initiating nor promoting activity in the assays.     

Arylation of [60]Fullerene with Br2/FeCl3/PhH: Formation of C58 Derivatives via CO Loss

Heating a mixture of [60]fullerene, bromine, ferric chloride and benzene under reflux for 24 h products a range of phenylated [60]fullerene derivatives. The main product is C₆₀Ph₅H but other components identified by mass spectrometry (and in some cases separated by HPLC) are: C_6oPh_n(n = 4, 6, 8, 10, 12), C₆₀Ph_nO₂(n = 4, 6, 8, 10, 12), C₆₀Ph_nOH (n = 7, 9, 11), C₆₀Ph_nH₂ (n = 4, 10), C₆₀Ph₄H₄, C₆₀Ph₅H₃, C₆₀Ph_n0₂H (n = 5, 9), C₆₀Ph₄C₆H₄O₂, C₆₀Ph₉OH₃, and C₆₀Ph₁₁ O₃H₂. In the corresponding reaction with toluene, the crude reaction mixture contained C₆₀(MeC₆H₄)₄ as a main product; C₆₀(ClC₆H₄)₅H was obtained from the reaction with chlorobenzene. Formation of these derivatives is believed to involve radical bromination of the fullerene, followed by electrophilic substitution of the hatogenofullerene into the aromatic, accompanied in some case by hydrolysis, elimination and epoxide formation; oxidation may also introduce ketone/dioxetane functionality. The EI mass spectra of C₆₀Ph₄O₂ and C₆₀Ph₈O₂show degradation to C₅₈Ph_n (n = 0-8), having structures believed to be related to the pseudofollerenes C₆₈Ph_n (n = 0-8) reported recently. These results suggest that some derivatisations of fullerenes confer stability, due to the relief of strain.     

Synthesis of Various Water-Soluble C60 Derivatives and Their Superoxide-Quenching Activity

In order to examine the utility of fullerene as a medicinal application, we evaluated the reaction between fullerene derivatives and active oxygen species in vitro. This paper describes the synthesis of various water-soluble C₆₀ derivatives (cationic and anionic) and evaluation of their superoxide (O₂^-) quenching activity. Cationic C₆₀ derivatives showed fairly high efficiency.     

Synthesis of Various Water-Soluble G60 Derivatives and Their Superoxide-Quenching Activity

In order to examine the utility of fullerene as a medicinal application, we evaluated the reaction between fullerene derivatives and active oxygen species in vitro. This paper describes the synthesis of various water-soluble C₆₀ derivatives (cationic and anionic) and evaluation of their superoxide (O₂^-) quenching activity. Cationic C₆₀ derivatives showed fairly high efficiency.     

Effect of Substituents on the Redox Potentials of C60 Derivatives

The electrochemical properties of four C₆₀ derivatives (compounds 1∼4) were investigated with cyclic voltammetry (CV), and compared with that of C₆₀. The reduction potentials of compound 1∼3 shifted to more negative positions than C₆₀, and their oxidation peaks appeared at the lower potentials. Significantly, the reduction potentials of compound 4 shifted to more positive positions than C₆₀, which is advantageous to form charge-transfer complexes with more donors. So the reduction properties in different solvents and in situ NIR absorption spectra of compound 4 were studied in more details. In addition, the AM1 molecular orbital calculation was performed on C₆₀ and compound 1∼4 for the explanation of the potential shifts. The reduction potentials of these compounds exhibited good linear relationships with the calculation LUMO or LUMO+1 energy levels.     

Benzene insertion within the CsC24 graphite intercalation compound: a kinetic neutron diffraction study

The reaction of CsC₂₄ with deuterated benzene (C₆D₆)vapours has been studied in situ by neutron diffraction on a 5 min per spectrum time scale. As in the case of KC₂₄ and RbC₂₄ compounds, we first observed a second-stage ternary CsC₂₄(C₆D₆)y compound (y<2), but it quickly turned into a first-stage ternary CsC₂₄(C₆D₆)₂ compound. Structure model calculations suggest that each Cs⁺ ion is surrounded by two benzene rings, with a tilt angle of 39°, with respect to the c axis.     

On the Action of γ Radiation on Solid C60 and C70 Fullerenes: A Comparison with Graphite Irradiation

C₆₀ and C₇₀ fullerene have been treated in sealed flasks under Ar with γ radiation using radiation dosages ranging from 10 to 1000 kGy. The treated samples studied by electronic and FT-IR spectroscopy have not shown any evidence about fullerenes decomposition or radiopolymerization. However, through Raman spectroscopy it was possible to observe that γ radiation induces C₆₀ dimerization and trimerization. It has additionally been discovered that γ-treated C₆₀ (oligomerized) can be easily photopolymerized in the solid state by post-irradiation with laser light at 514 nm while this phenomenon has not been observed by using laser light at 782 nm and considerably higher laser power. Previously to this study, C₆₀ photopolymerization was known to occur only by using ultraviolet light.

For comparison also graphite was irradiated with 1000 kGy of γ radiation. Irradiated graphite shows considerably changes in its Raman spectrum, showing the formation of glassy carbon domains, perhaps carbon onions. The l_d bandshift to 1310 cm^-1 could be interpreted in terms of formation of hexagonal diamond.     

Water-Soluble C60 and Macrophages: Morphologic Features of FC4S-Treated Peritoneal Macrophages in vitro and in vivo - A Preliminary Report

Morphologic investigation of water-soluble hexasulfonated C₆₀ (FC₄S) effects on rat peritoneal macrophages in vitro and in vivo was conducted by transmission electron microscopy. In the case of in vitro studies, two groups of spontaneous peritoneal macrophages were separately cocultured with FC₄S in a concentration of either 0, or 100 ng/ml for 24 h. The other two groups were cocultured with either FC₄S (100 ng/ml) for 12 h, or Pseudomonas aeruginosa exotoxin A (ETA) 100 ng/ml for 24 h. The former 12 h FC₄S-treated group was subsequently cultured with ETA for an another 12 h. All these 4 groups 24 h of cocultured monolayer cells were fixed in glutaraldehyde 2.5%, post fixed in 1% OsO₄ and processed for morphologic evaluation. The results revealed that the viability of FC₄S-treated cells in a healthy state, containing numerous cytoplasmic electron-dense (ED) bodies. The origin and nature of these ED bodies were not known. Comparable observation was obtained with the FC₄S-pretreated and ETA-treated the cells as viable and healthy. This suggested the existence of plausible antioxidative bio-reactions involving phagocytosed hexa(sulfobutyl)[60] fullerenes in cocultured macrophages. In the case of in vivo studies, the cells removed from rats that were ip injected with 60 mg/kg of FC₄S were found to be typical active macrophages that bore numerous lysosomes and phagolysosomes in a variable degree of phagocytosing state. The presence of phagolysosomes were attributable to the FC₄S exposure. The affected cells were diagnosed as “phagolysosomal macrophagopathy”.     

Fullerane, the Hydrogenated C60 Fullerene: Properties and Astrochemical Considerations

Hydrogenated C₆₀ fullerene, C₆₀H₃₆ was prepared in different solvents using Zn/HCl as reducing agents. The structure of C₆₀H₃₆ was confirmed both by electronic and FT-IR spectroscopy and the purity of the reaction product was checked by HPLC analysis. It has been confirmed that C₆₀H₃₆ is not stable in air, especially in presence of light which enhances the oxidation. The oxidation of C₆₀H₃₆ was studied by FT-IR spectroscopy and by differential scanning calorimetry (DSC) in air; the formation of hydroxyl groups on the fullerene cage and ketonic groups (involving cage breakdown) have been detected. Furthermore, the action of O₃ on C₆₀H₃₆ was investigated and it has been found that O₃ exerts practically the same effect of air but causing an enhanced cage breakdown. The thermal stability of C₆₀H₃₆ was checked by a thermogravimetric analysis (TGA) coupled with a differential thermal analysis (DTA) under N₂ flow. The vaporization of C₆₀H₃₆ occurs at very high temperature: the DTA trace has shown an endothermic peak at 540°C (at a heating rate of 20°C/min). C₆₀H₃₆ shows an electronic absorption spectrum with a maximum at about 217 nm and it is able to match both in position and in half width the peak at 217.5 nm observed in the spectrum of the interstellar extinction of light which was attributed to hydrogenated, radiation processed and thermally annealed carbon dust. Similarly, the absorption spectrum of C₆₀H₃₆ is able to match several infrared emission bands (called UIBs) detected from certain astrophysical objects like the protoplanetary nebulae (PPNe). It is proposed that hydrogenated fullerenes can be used as model compounds in the laboratory simulation studies of interstellar carbon dust.     

[60]Fullerene as a Novel Photoinduced Antibiotic

The antibacterial activity of [60]fullerene (C₆₀), dissolved with poly(vinylpyrrolidone) K30 (PVP), was studied. Under photo-irradiation, C₆₀/PVP aqueous solutions showed antibacterial activity, whereas PVP solution alone or fullerene solutions in the absence of light showed no activity. These results reveal that C₆₀ is a potentially good device as a photoinduced antibacterial agent.     

Synthesis of Fullerenols from Halofullerenes

Halogenated fullerenes were used as reagents to prepare fullerenols. Depending on reaction conditions two types of substances (complex mixtures of products with average compositions C₆₀O_nH_m, n=10-26, m=14-30 and C₆₀O_nH_mM_k, M=K, Na; n=17-24, m=16-28, k=3-8) possessing essentially different water solubility were obtained. Highly soluble metal-containing species are most likely ionic compounds similar to metal derivatives of alcohols-alcoholates. An electron withdrawing effect of the carbon cage could make alkali metal fullerenolates (C₆₀(OH)_x(OM)_y) inert towards hydrolysis. Halogens were selectively substituted when fullerene bromides and chlorides were treated with silver trifluoroacetate. Fullerenol esters C₆₀(OOCCF₃)_n formed were then hydrolyzed to form C₆₀(OOCCF₃)_x(OH)_y. Attempts to cleave all ester groups in C₆₀(OOCCF₃)_x(OH)_y failed in acidic media, while alkaline hydrolysis was accompanied by unselective polyhydroxylation of the fullerene cage.     

Preparation and Characterization of LaxC60 Thin Films Fabricated by Layer-by-Layer Deposition

A modification of physical properties of solid-state C₆₀ when La was doped to C₆₀ thin film as a trivalent metal was examined. the thin film was fabricated by using Layer-by-Layer deposition technique with the multi-sources evaporation system. We found that the C₆₀ film changes its electrical character from the insulator to the semiconductor rapidly upon La doping. the temperature dependence of the electrical conductivity is semiconductive with the activation energy of about 0.3eV.     

Inhibition of Drug-Metabolizing Enzymes in Mouse Liver by a Water Soluble Fullerene C60

The microsomal cytochrome P450-dependent monooxygenase system is responsible for the metabolism a variety of xenobiotics including drugs and carcinogens. Fullerenol-1 is a water soluble polyhydroxylated C₆₀ derivative synthesized by a sequence of reactions involving the electrophilic attack of nitronium tetrafluoroborate on fullerenes in the presence of organocarboxylic acids. The present study has evaluated the acute toxicity of fullerenol-1 and determined the effects of the C₆₀ compound on the P450-dependent drug-metabolzing activities. Pretreatments with 0.5 and 1.0g/kg fullerenol-1 decreased P450 and cytochrome b₅ contents, and NADPH-cytochrome P450 reductase, as well as drug metabolizing activities toward test substrates benzo[a]pyrene, 7-ethoxycoumarin, aniline, and erythromycin in liver microsomes. Pretreatments with 0.01 and 0.1 g/kg fullerenol-1 had no effect on these monooxygenases. Immunoblotting anlysis of the microsomal proteins revealed that pretreatments with fullerenol-1 did not alter the protein levels of P450s 1A, 2E and 3A. Additions of fullerenol-1 to mouse liver microsomes suppressed monooxygenases activities toward benzo[a]pyrene, 7-ethoxycoumarin, aniline, and erythromycin with IC₅₀ values of 42, 94, 102 and 349 μM, respectively. These results demonstrate that fullerenol-1 can decrease the activities of microsomal drug-metabolizing enzymes in vivo and in vitro. Proper adjustment of the functionalized fullerene compound may facilitate the biomedical application of the new material.     

Thermally Activated Decay Processes of Isolated Superhot C60 in Molecular Beams

We have studied thermally activated decay processes of an ensemble of isolated superhot C₆₀ molecules in molecular beams by several different methods. Highly vibrationally excited C₆₀ molecules in effusive or supersonic beams (with average vibrational energy of 10-20 eV) were generated in an all ceramic, two-stage high temperature nozzle source. the decay kinetics due to various decay processes of the initially canonical ensemble was followed by a mass spectrometric methods for a large range of initial temperatures (T_o=1100 - 1950 K). the processes studied are: (1) fragmentation (C₂ emission) of the neutral C₆₀ (2) C₂ emission from the C⁺₆₀ ions (3) black-body like radiative cooling, and (4) delayed electron emission. the experiments described here are: (a) Depletion of the integrated C₆₀ flux. (b) Analysis of C₆₀ time-of-flight distributions. (c) Dependence of electron impact induced ionization/ fragmentation of C₆₀ upon its initial thermal excitation, and (d) Thermal energy dependence of delayed electron emission. It is shown that thermal kinetics models using a single set of independently measured parameters uniquely reproduce all the experimental observations. the models take into account the different cooling processes and their time evolution. We analyze in detail the evolution of the initially canonical vibrational energy distribution during the flight time to the detector as it is gradually being distorted due to evaporative and radiative cooling mechanisms. It is concluded that the correct parameters to be used for describing the thermally activated decay kinetics of superhot C₆₀ are activation energy of E_o = 4.3 - 4.8 eV for the neutral fragmentation channel C₆₀ → C₅₈ + C₂ and E₁=4.0 - 4.3 for the ion fragmentation channel C⁺₆₀→ C⁺₅₈ + C₂, and corresponding pre-exponential factors of A_o = A₁ = 2.5 × 10¹³ sec^-1. the emissivity coefficient for black body like radiation was found to be ε = 4.5 × 10^-5.     

Preparation and Characterization of Inorganic Fluorides—Fullerenes Compounds

Reaction of metallic fluorides: WF₆ TaF₅, NbF₅ and TiF₄ with C₆₀/C₇₀ extract was performed at appropriate temperatures. M0F₅ and BF₃ fluorides do not react. Chemical formulas based on mass uptake show MF_n/C₆₀ ratios up to 2.00. Compounds were analysed by means of X-ray diffraction, FT-IR and NMR spectroscopies. The presence of neutral fluorides and associated anionic species is put forward and it is shown that MF_n compounds do not act as fluorination agents. Electrical conductivity measurements are also presented.     

CO-DEPOSITION OF FULLERENES AND SULFUR FROM DILUTED SOLUTION

A new method to synthesize fullerene and sulfur compounds has been developed. Using this method, C₆₀S₁₆ and C₇₀S₁₆ compounds were grown from dilute fullerene and sulfur toluene solution. Their atomic structures were analyzed by x-ray diffraction with the single crystal. The C₆₀S₁₆ crystal is C-centered monoclinic structure of a=2.0874 nm, b=2.1139 nm, c=1.05690 nm and β=111.93°, and the C₇₀S₁₆ has a primitive monoclinic, P2₁/c, with lattice parameters of a=1.5271 nm, b=1.49971 nm, c=2.18024 nm and β=109.791°. In this compound, the structure of fullerenes is maintained and sulfur atoms form S₈ rings placed around the fullerenes.     

Surface Ionization Mass Spectrometric Studies of the Li/C60 System

We have studied the Li/C₆₀ system by the surface ionization mass spectrometry. We have investigated a possibility of the Li@C₆₀ formation via the collisions between Li⁺and C₆₀^- ions in a plasma state, which was predicted by an ab initio molecular dynamics simulation. The LiC₆₀ complex was unambiguously observed. Our results do not allow direct determination of the LiC₆₀ structure but indicate that Li is inside the C₆₀ cage. We have determined the ionization potential of Li@C₆₀ complex (IP = 5.9 ± 0.1 eV), which agrees well with the calculated value of the IP of Li@C₆₀.     

简易合成Bi/Bi2MoO6/TiO2复合纳米纤维及其增强的可见光催化性能

以电纺TiO₂ 纳米纤维为基质, 葡萄糖为还原剂, 采用简单一步溶剂热法制备了等离子体Bi/Bi₂MoO₆/TiO₂复合纳米纤维。利用X射线衍射、场发射扫描电镜、透射电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱和光致发光谱等对样品进行表征。以RhB和4-CP为模拟有机污染物, 评价材料的光催化性能。结果表明: 部分Bi ³⁺被葡萄糖还原成金属Bi纳米粒子, 原位沉积在Bi₂MoO₆纳米片上, 同时构筑在TiO₂纳米纤维表面。金属Bi的等离子体共振效应, 有效提高了样品的光催化活性。可见光照50 min, 样品对RhB的降解率为95.8%, 五次循环后仍保持在92%以上; 可见光照180 min, 样品对4-CP的降解率达68.8%。证实该材料具有良好的可见光催化活性和稳定性。     

ISOLATION AND CHARACTERISATION OF C60(CF3)2

From the products of reactions of [60]fullerene with either K₂PtF₆ at 470 °C or AgF at 520 °C, we have isolated C₆₀(CF₃)₂, the simplest trifluoromethylfullerene, which gives a single ¹⁹F NMR line at -69.5 ppm. The HPLC retention time is less than that of C₆₀F₂ confirming the trend observed for other fluoro- vs. trifluoromethylfullerenes namely that the latter elute more rapidly. Other trifluoromethyl- containing species, C₆₀(CF₃)₄O, C₆₀F₅CF₃, C₆₀(CF₃)₄H₂, C₆₀(CF₃)₆H₂, and C₆₀(CF₃H)₃ were detected in the product mixture.