Water-soluble Fullerene Research Articles

Distinct Cytotoxic Mechanisms of Pristine versus Hydroxylated Fullerene

The mechanisms underlying the cytotoxic action of pure fullerene suspension (nano-C60) and water-soluble polyhydroxylated fullerene [C60(OH)n] were investigated. Crystal violet assay for cell viability demonstrated that nano-C60 was at least three orders of magnitude more toxic than C60(OH)n to mouse L929 fibrosarcoma, rat C6 glioma, and U251 human glioma cell lines. Flow cytometry analysis of cells stained with propidium iodide (PI), PI/annexin V-fluorescein isothiocyanate, or the redox-sensitive dye dihydrorhodamine revealed that nano-C60 caused rapid (observable after few hours), reactive oxygen species (ROS)-associated necrosis characterized by cell membrane damage without DNA fragmentation. In contrast, C60(OH)n caused delayed, ROS-independent cell death with characteristics of apoptosis, including DNA fragmentation and loss of cell membrane asymmetry in the absence of increased permeability. Accordingly, the antioxidant N-acetylcysteine protected the cell lines from nano-C60 toxicity, but not C60(OH)n toxicity, while the pan-caspase inhibitor z-VAD-fmk blocked C60(OH)n-induced apoptosis, but not nano-C60-mediated necrosis. Finally, C60(OH)n antagonized, while nano-C60 synergized with, the cytotoxic action of oxidative stress-inducing agents hydrogen peroxide and peroxynitrite donor 3-morpholinosydnonimine. Therefore, unlike polyhydroxylated C60 that exerts mainly antioxidant/cytoprotective and only mild ROS-independent pro-apoptotic activity, pure crystalline C60 seems to be endowed with strong pro-oxidant capacity responsible for the rapid necrotic cell death.

Cytotoxicity of water-soluble fullerene in vascular endothelial cells

Nanoscale materials are presently under development for diagnostic (nanomedicine) and electronic purposes. In contrast to the potential benefits of nanotechnology, the effects of nanomaterials on human health are poorly understood. Nanomaterials are known to translocate into the circulation and could thus directly affect vascular endothelial cells (ECs), causing vascular injury that might be responsible for the development of atherosclerosis. To explore the direct effects of nanomaterials on endothelial toxicity, human umbilical vein ECs were treated with 1-100 microg/ml hydroxyl fullerene [C60(OH)24; mean diameter, 7.1 +/- 2.4 nm] for 24 h. C60(OH)24 induced cytotoxic morphological changes such as cytosolic vacuole formation and decreased cell density in a dose-dependent manner. Lactate dehydrogenase assay revealed that a maximal dose of C60(OH)24 (100 microg/ml) induced cytotoxic injury. Proliferation assay also showed that a maximal dose of C60(OH)24 inhibited EC growth. C60(OH)24 did not seem to induce apoptosis but caused the accumulation of polyubiquitinated proteins and facilitated autophagic cell death. Formation of autophagosomes was confirmed on the basis of Western blot analysis using a specific marker, light chain 3 antibody, and electron microscopy. Chronic treatment with low-dose C60(OH)24 (10 microg/ml for 8 days) inhibited cell attachment and delayed EC growth. In the present study, we have examined, for the first time, the toxicity of water-soluble fullerenes to ECs. Although fullerenes changed morphology in a dose-dependent manner, only maximal doses of fullerenes caused cytotoxic injury and/or death and inhibited cell growth. EC death seemed to be caused by activation of ubiquitin-autophagy cell death pathways. Although exposure to nanomaterials appears to represent a risk for cardiovascular disorders, further in vivo validations are necessary.

Toxicity of an engineered nanoparticle (fullerene, C60) in two aquatic species, Daphnia and fathead minnow

Water-soluble fullerene (nC60) has been shown to induce lipid peroxidation (LPO) in brain of juvenile largemouth bass (LMB, Micropterus salmoides) [Oberdörster, E., 2004. Manufactured nanomaterials (fullerenes, c60) induce oxidative stress in brain of juvenile largemouth bass. Environ. Health Persp. 112, 1058-1062]; and upregulate genes related to the inflammatory response and metabolism, most notably CYP2K4 [. Nanotoxicology: an emerging discipline evolving from 116 studies of ultrafine particles. Environ. Health Persp. 113, 823-839]. The initial study in LMB was performed using tetrahydrofuran (THF)-solubilized nC60, although C60 can also be solubilized by stirring in water. The current study investigates differences in acute toxicity to Daphnia magna between THF-solubilized and water-stirred-nC60 as a range-find for further assays in adult male fathead minnow (FHM, Pimephales promelas). The daphnia 48-h LC50 for THF-nC60 was at least one order of magnitude less (0.8 ppm) than that for water-stirred-nC60 (> 35 ppm). FHM were dosed with either 0.5 ppm of THF- or water-stirred-nC60 for 48 h. There was 100% mortality in the THF-nC60-exposed fish between 6 and 18 h, while the water-stirred-nC60-exposed fish showed no obvious physical effects after 48 h. Water-stirred-nC60 elevated LPO in brain, significantly increased LPO in gill, and significantly increased expression of CYP2 family isozymes in liver as compared to control fish.

Low-temperature postradiation quasi-living radical polymerization of acrylic monomers in the presence of fullerene C 60

Water-soluble fullerene C 60 -containing polymers of acrylamide and acrylic acid were obtained by low-temperature radiation-induced quasi-living radical polymerization.

Pharmacological Studies on Fullerene (C60), a Novel Carbon Allotrope, and Its Derivatives

Fullerene (C(60)), a condensed ring aromatic compound with extended pi systems, is a novel carbon allotrope. Because of its poor solubility in polar solvents, investigation of the biological and pharmacological properties of fullerene has been difficult. Recently, water-soluble fullerene derivatives have been synthesized, and we and others have found that they have potent and selective pharmacological effects on organs, cells, enzymes, and nucleic acids. In the presence of fullerene C(60) derivative (10(-5) M), endothelium-dependent relaxations induced by agonists in the vascular system were eliminated and acetylcholine-induced contractile response of smooth muscle was observed. Some investigators have reported free radical-scavenging activity and direct nitric oxide-quenching activity of fullerene derivatives. Knowledge of the chemical modifications, biological significance, and materials applications of functionalized fullerenes is growing rapidly; and these compounds are emerging as new tools in the field. The focus of this review is to introduce several pharmacological effects of fullerenes and to discuss the possible mechanisms of the pharmacological actions caused by previously synthesized fullerenes.

A highly water-soluble C60–NVP copolymer: a potential material for photodynamic therapy

Water-soluble C60 polymers, which have the highest solubility of fullerene reported to date (7.8 mM of C60 in water), were prepared via copolymerization, and showed significant visible light-induced O2*- generation and DNA cleavage, indicating the potential of these water-soluble fullerene derivatives as agents for photodynamic therapy.

Genotoxicity in Cell Lines Induced by Chronic Exposure to Water-Soluble Fullerenes Using Micronucleus Test

Genotoxicity in Cell Lines Induced by Chronic Exposure to Water-Soluble Fullerenes Using Micronucleus Test

Ecotoxicology of carbon-based engineered nanoparticles: Effects of fullerene (C 60) on aquatic organisms

To more fully assess the toxicity of water-soluble fullerene (nC 60), acute toxicity assays were performed on several environmentally relevant species. Included were the freshwater crustaceans Daphnia magna and Hyalella azteca, and a marine harpacticoid copepod, and two fish species, fathead minnow Pimephales promelas and Japanese medaka Oryzias latipes. The latter two species were used to assess sublethal effects of fullerene exposure by also assessing mRNA and protein expression in liver. Because prior studies found that both sonication and using tetrahydrofuran to solubilize fullerene increased the toxicity of nC 60, the nC 60 used in this study was prepared by stirring. For the invertebrate studies, nC 60 could not be prepared at high enough concentration levels to cause 50% mortality (LC 50) at 48 or 96 h. The maximum concentrations tested were 35 ppm for freshwater and 22.5 ppm for full-strength (35 ppt) seawater, since at higher concentrations the nC 60 precipitated out of solution. Daphnia 21-day exposures resulted in a significant delay in molting and significantly reduced offspring production at 2.5 and 5 ppm nC 60, which could possibly produce impacts at the population-level. For the fish, we found that neither the mRNA nor protein-expression levels of cytochrome P450 isozymes CYP1A, CYP2K1 and CYP2M1 were changed. The peroxisomal lipid transport protein PMP70 was significantly reduced in fathead minnow, but not medaka, indicating potential changes in acyl-CoA pathways.

Assembly of Fullerene Arrays Templated by DNA Scaffolds

A water-soluble fullerene, C60-N,N-dimethylpyrrolidinium iodide, was dispersed in aqueous media in the form of vesicles. By mixing and incubating the fullerene vesicle and a 2D DNA lattice bearing a phosphate-labeled protruded strand together, pearl-like arrays of fullerene domains can be obtained on the DNA template.

Spectrophotometric Study of Fluorescence Sensing and Selective Binding of Biochemical Substrates by 2,2‘-Bridged Bis(β-cyclodextrin) and Its Water-Soluble Fullerene Conjugate

A bis(beta-cyclodextrin)-fullerene conjugate (3) linked at the secondary hydroxyl side was prepared in a good yield from its precursor N,N'-bis(2-(2-aminoethylamino)ethyl)malonamide-bridged bis(beta-cyclodextrin) (2). Spectrophotomeric studies on the conformation and the inclusion complexation behavior of 3 with a variety of organic and biochemical substrates by means of UV-vis, FT-IR, NMR, fluorescence, and circular dichroism spectroscopy showed that the bis(beta-cyclodextrin)-fullerene conjugate displayed an intramolecular capsule-type conformation in aqueous solution. Because of the multiple binding of bis(beta-cyclodextrin) with substrates, 2 can act as an efficient fluorescence sensor for biochemical substrates, while its fullerene conjugate 3 displays a capability of cleaving DNA under visible-light irradiation.

Cationic Fullerenes Are Effective and Selective Antimicrobial Photosensitizers

Fullerenes are soccer ball-shaped molecules composed of carbon atoms, and, when derivatized with functional groups, they become soluble and can act as photosensitizers. Antimicrobial photodynamic therapy combines a nontoxic photosensitizer with harmless visible light to generate reactive oxygen species that kill microbial cells. We have compared the antimicrobial activity of six functionalized C(60) compounds with one, two, or three hydrophilic or cationic groups in combination with white light against gram-positive bacteria, gram-negative bacteria, and fungi. After a 10 min incubation, the bis- and tris-cationic fullerenes were highly active in killing all tested microbes (4-6 logs) under conditions in which mammalian cells were comparatively unharmed. These compounds performed significantly better than a widely used antimicrobial photosensitizer, toluidine blue O. The high selectivity and efficacy exhibited by these photosensitizers encourage further testing for antimicrobial applications.

Synthesis and Self-Assembled Film Fabricated from Water-Soluble Poly( P-phenylene vinylene) and Fullerene Derivative

Fullerene-containing ammonium was synthesized and the photocurrent generation of self-assembled multilayer film fabricated from [ll-(2,2-dimethyl-[60]fulleropyrrolidin-l-yl)-undecyl]-trimethyl-animonium ( FA) and water-soluble poly( P-phenylene vinylene) using alternate deposition method was also investigated. The self-assembled film exhibits a steady and rapid anodic 2.5 μA cm −2 photocurrent response.

Antioxidant effects of water-soluble fullerene derivatives against ultraviolet ray or peroxylipid through their action of scavenging the reactive oxygen species in human skin keratinocytes

Chemically generated hydroxyl radicals were scavenged by PEG-modified fullerene, hydroxy-fullerene and isostearate-mixed fullerene as efficiently as ascorbic acid (Asc) or its 2- O-phosphorylated derivative (A2P) as shown by the DMPO-spin trap/ESR method. Enzymatically generated superoxide anion radicals were also scavenged by PEG-modified or PVP-entrapped fullerene similarly as done by Asc or A2P. Some reactive oxygen species (ROS) such as hydroperoxides and hydrogen peroxides were generated preferably in the nuclei of UVB-irradiated human skin keratinocytes HaCaT, and repressed by PVP- or γ-cyclodextrin-fullerene. In contrast, the cytoplasm in the keratinocytes accumulated the ROS that were generated by the peroxylipid model compound t-BuOOH, and underwent the ROS repression by PVP-fullerene more markedly than by A2P. Thus several fullerene derivatives, especially PVP-fullerene, were shown to diminish the ROS amounts in terms of the molecular and cellular levels against either UVB or t-BuOOH, suggesting the expectation for development as rejuvenation cosmetics.

Photovoltaic Cells Based on Sequentially Adsorbed Multilayers of Conjugated Poly(p-phenylene ethynylene)s and a Water-Soluble Fullerene Derivative

We describe the layer-by-layer (LBL) fabrication of multilayer films and photovoltaic cells using poly(phenylene ethynylene)-based anionic conjugated polyelectrolytes as electron donors and water-soluble cationic fullerene C60 derivatives as acceptors. LBL film deposition was found to be linearly related to the number of bilayers as monitored by UV-vis absorption. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) of the multilayer films revealed an aggregated but relatively uniform morphology devoid of any long-range phase separation. The maximum incident monochromatic photon to current conversion efficiency (IPCE) of the photovoltaic cells was 5.5%, the highest efficiency reported to date for cells fabricated by using the LBL fabrication technique, and since the thin film cells do not provide complete absorption of the incident light, the current generation per photon absorbed may be as much as 10%. The cells exhibited open circuit voltages of 200-250 mV with highest measured short circuit currents up to 0.5 mA/cm2 and fill factors around 30%. The power conversion efficiencies measured at AM 1.5 solar conditions (100 mW/cm2) varied between 0.01 and 0.04%, and similar to the IPCE results, the efficiency is a function of the thickness of the PV active layer.

Hemolytic Effects of Water-Soluble Fullerene Derivatives

A series of water-soluble fullerene C(60) derivatives has been investigated for their cytotoxic and hemolytic properties, with the aim to correlate structure with toxicity. We observed that cationic chains induce significant toxicity while the presence of neutral or anionic moieties did not produce any response in our model. A validation of these experimental observations has been performed by theoretical studies in which hydrophilic and hydrophobic surface areas were correlated quantitatively with hemolytic properties.

Functionalized Fullerenes in Water. The First 10 Years of Their Chemistry, Biology, and Nanoscience

AbstractFor Abstract see ChemInform Abstract in Full Text.

Complex formation between water-soluble sulfonated calixarenes and C60 fullerene

The inclusion complexes of sulfonated thiacalix[4]arene 1 and calix[6]arene 2 sodium salts with C60 fullerene were investigated by photoluminescence (PL) and quantum-chemical methods. The stoichiometries of calixarene/C60 complexes were found to be 2:1 for 1 and 1:1 for 2. Related quantum-chemical investigations show that C60 fullerene is included in a cavity composed of two half-bowl molecules of 1. The C60 fullerene ball is located deep within the cavity of 2 and the negatively charged sulfonate arms probably inhibit the formation of the bowl-shaped capsule that was observed in the case of 1.

Functionalized fullerenes in water. The first 10 years of their chemistry, biology, and nanoscience.

Fullerenes are entirely insoluble in water, but suitable functionalization makes the molecules soluble. Studies on water-soluble fullerene derivatives led to the discovery of the interaction of organofullerenes with DNA, proteins, and living cells, which was first reported in the summer of 1993. Subsequent studies have revealed interesting biological activity aspects of organofullerenes owing to their photochemistry, radical quenching, and hydrophobicity to form one- to three-dimensional supramolecular complexes. In these areas of research, synthetic organic chemistry has played an important role in the creation of tailor-made molecules.

First soluble M@C60 derivatives provide enhanced access to metallofullerenes and permit in vivo evaluation of Gd@C60[C(COOH)2]10 as a MRI contrast agent.

M@C(60) and related endohedral metallofullerenes comprise a significant portion of the metallofullerene yield in the traditional arc synthesis, but their chemistry and potential applications have been largely overlooked because of their sparse solubility. In this work, procedures are described to solublize Gd@C(60) species for the first time by forming the derivative, Gd@C(60)[C(COOCH(2)CH(3))(2)](10), and its hydrolyzed water-soluble form, Gd@C(60)[C(COOH)(2)](10). Imparting water solubility to Gd@C(60) permits its evaluation as a magnetic resonance imaging (MRI) contrast agent. Relaxometry measurements for Gd@C(60)[C(COOH)(2)](10) reveal it to possess a relaxivity (4.6 mM(-1) s(-1) at 20 MHz and 40 degrees C) comparable to that of commercially available Gd(III) chelate-based MRI agents. An in vivo MRI biodistribution study in a rodent model reveals Gd@C(60)[C(COOH)(2)](10) to possess the first non-reticuloendothelial system (RES) localizing behavior for a water-soluble endohedral metallofullerene species, consistent with its lack of intermolecular aggregation in solution as determined by light-scattering measurements. This first derivatization and use of a M@C(60) species suggests new potential for metallofullerene technologies by reducing reliance on the chromatographic purification procedures normally employed for the far less abundant M@C(82) and related endohedrals. The recognition that water-soluble fullerene derivatives can be designed to avoid high levels of RES uptake is an important step toward fullerene-based pharmaceutical development.

A selective reaction of polyhydroxy fullerene with cycloaliphatic epoxy resin in designing ether connected epoxy star utilizing fullerene as a molecular core

A novel ether connected epoxy star like polymer was synthesized by selective reaction of water soluble polyhydroxy fullerene (fullerenol) with a commercial grade cycloaliphatic epoxy resin (CY-230, Ciba Geigy) in heterogeneous medium at ambient alkaline condition using tetrabutylammonium hydroxide as phase transfer catalyst. The reaction went well in such conditions and the hydroxy groups of fullerenol underwent selective nucleophilic addition reaction with polar carbonyl groups of the epoxy resin with the formation of a hemiketal. The progress of the reaction was monitored by FTIR analysis of the product formed. The disappearance of characteristic FTIR bands of fullerenol (at 1593.2, 1381.2, and 1068 cm −1) and the typical carbonyl peak (at 1725 cm −1) of parent epoxy resin and also changes of broad hydroxy peak (at 3431 cm −1) of fullerenol into a sharp peak (at 3396.6 cm −1, indicating reduced hydrophilicity) in the reaction product clearly demonstrated the chemical attachment of the epoxy units to the fullerene core. Multiple epoxy units (about 8–10) were attached to fullerene core. Non-reactivity of fullerenol towards DGEBA epoxy resin (LY 556 Ciba Geigy) in similar conditions further supports our result. The thermal properties of the product were influenced by the presence of fullerenol and exhibits higher thermal stability compared to parent epoxy. A probable reaction mechanism for the reaction has also been discussed.