Fullerene Nanomaterials Research Articles

Boosting Photocatalytic Water Splitting of Polymeric C60 by Reduced Dimensionality from Two-Dimensional Monolayer to One-Dimensional Chain.

The recent synthesis of monolayer fullerene networks (Hou, L., et al. Nature 2022, 606, 507) provides new opportunities for photovoltaics and photocatalysis because of their versatile crystal structures for further tailoring of electronic, optical, and chemical function. To shed light on the structural aspects of the photocatalytic water splitting performance of fullerene nanomaterials, we compare the photocatalytic properties of individual polymeric fullerene chains and monolayer fullerene networks from first-principles calculations. We find that the photocatalytic efficiency can be further optimized by reducing the dimensionality from two-dimensional (2D) to one-dimensional (1D). The conduction band edge of the polymeric C60 chain provides an external potential for the hydrogen reduction reaction much higher than that of its monolayer counterparts over a wider range of pH values, and there are 2 times more surface active sites in the 1D chain than in the 2D networks from a thermodynamic perspective. These observations identify the 1D fullerene polymer as a more promising candidate as a photocatalyst for the hydrogen evolution reaction in comparison to monolayer fullerene networks.

Molecular modeling of Si60 fullerene and Nb-doped Si60 fullerene nanomaterials for SO2, NO2 and CO2 gas sensing

CO2, NO2 and SO2 are by-products from the petrochemical industries that have been associated with both global warming and several respiratory dysfunctions. Hence, several efforts are being put forth to detect their excesses at minimal concentrations. In this regard, this study presents a theoretical analysis based on quantum and molecular mechanical calculations of the sensing efficacy of silicon nanostructures towards the effective detection of these gases at low concentrations. To enhance the attributes of the nanomaterial, transition metal (Nb) was endohedrally doped on the silicon Si60 nanomaterial to enhance the surface conductivity and sensitivity. The results indicate that the metal-doped nanostructures have improved sensitivity towards the studied gases. The adsorption of NO2, SO2 and CO2 followed a declining trend; NO2@NbdopSi59 > SO2@NbdopSi59 > CO2@NbdopSi59 > NO2@Si60 > SO2@Si60 > CO2@Si60 respectively. The computed adsorption enthalpies were found to be −25.36, −136.26 and −183.67 kcal/mol respectively for CO2@NbdopSi59, NO2@NbdopSi59 and SO2@NbdopSi59 systems. Comparatively, SO2 and NO2 preferred to be adsorbed on Si60 than CO2. The results of other electronic properties such as energy gap and conductivity were also found to be in tandem with the adsorption and stability studies. The sensing mechanism and computed desorption times were also found to be within 1.02 s to 2.72 s, clearly indicating a quick desorption from the metal-doped surface. Contrary, desorption from the pristine nanocluster was found to be slower due to strong chemisorption bonds between the gases and surface. While the electronic properties affirmed the conducting and stable nature of the surfaces, molecular dynamics simulation was further employed for stability evaluation. These results also unveiled the stable nature of the nanocluster and confirmed that the studied metal-doped nanoclusters possess the ideal properties to be employed as sensors for SO2 NO2 and CO2 gases.

Surface engineering of non-platinum-based electrocatalysts for sustainable hydrogen production: Encapsulation, doping, and decoration approach

The hydrogen evolution reaction's electrocatalytic reduction of water to molecular hydrogen may one day provide a long-term sustainable source of energy. However, the use of precious platinum catalysts makes it difficult to commercialize. So far, all alternatives to platinum are based on non-precious metals and transition metals. Hence, tuning the catalytic activity of nanomaterials through surface engineering might offer significant advantages. Herein, we step-wisely modulate the surface of all carbon fullerene nanomaterial by encapsulation, doping and decoration with alkali and transition metals to produce a hybrid catalyst which demonstrated excellent hydrogen evolution activity with comparable Gibbs free energy with both experimentally developed and theoretically modelled electrocatalyst. The adsorption of H* intermediate on the doped and decorated metal sites has been investigated in comparison with the pristine C24 fullerene structure. The electronic properties, the density of state (PDOS), reaction-free energy (ΔG) and transition states have all been carefully considered at appropriate theoretical levels. The ΔG of hydrogen adsorption on H@IndecNidopMgencC24 was found to be closer to zero (0.0328 eV) because of the concomitant effect of the encapsulation, doping and decoration with transition metals thus, demonstrating the effectiveness of this approach to tuning catalytic activity. The encapsulated metal enhanced the catalyst surface's conductivity and electronic attributes, leading to improved HER activity. The catalytic HER was also found to follow the Volmer-Tafel pathways, resulting in a lower free energy barrier. Overall, this work demonstrates a simple structure-activity relationship between metallic effects and substrate engineering and could open new dimensions for the development of novel non-platinum-based electrocatalysts.

Interactions between modified fullerenes and proteins in cancer nanotechnology

Fullerenes have numerous properties that fill the gap between small molecules and nanomaterials. Several types of chemical reaction allow their surface to be ornamented with functional groups designed to change them into 'ideal' nanodelivery systems. Improved stability, and bioavailability are important, but chemical modifications can render them practically soluble in water. 'Buckyball' fullerene scaffolds can interact with many biological targets and inhibit several proteins essential for tumorigeneses. Herein, we focus on the inhibitory properties of fullerene nanomaterials against essential proteins in cancer nanotechnology, as well as the use of dedicated proteins to improve the bioavailability of these promising nanomaterials.

Uncovering nanotoxicity of a water-soluble and red-fluorescent [70]fullerene nanomaterial

Engineered fullerene materials have attracted the attention of researchers in the biomedical sciences, especially when their synthetic methodology is developed to endow them with significant levels of water-solubility and bioavailability. In this study, we synthesized and characterized a water-soluble and red-fluorescent [70]fullerene nanomaterial, which fluoresced at 693 nm with a quantum yield of 0.065 and a large Stokes shift (around 300 nm). The fullerene nanomaterial generated mainly singlet oxygen after illumination with blue LED light, while superoxide anion radical production was minimal. The transmission electron microscopy as well as fluorescent studies of Drosophila melanogaster revealed that prepared [70]fullerene nanoparticles had better bioavailability than pristine [70]fullerene nanoparticles. The designed nanomaterials were observed in the apical, perinuclear, and basal regions of digestive cells, as well as the basal lamina of the digestive system's epithelium, with no damage to cell organelles and no activation of degenerative processes and cell death. Our findings provide a new perspective for understanding the in vivo behavior of fullerene nanomaterials and their future application in bioimaging and light-activated nanotherapeutics.

Identification and Biological Evaluation of a Water-Soluble Fullerene Nanomaterial as BTK Kinase Inhibitor.

Thanks to recent advances in synthetic methodology, water-soluble fullerene nanomaterials that interfere with biomolecules, especially DNA/RNA and selected proteins, have been found with tremendous potential for applications in nanomedicine. Herein, we describe the synthesis and evaluation of a water-soluble glycine-derived [60]fullerene hexakisadduct (HDGF) with T h symmetry, which is a first-in-class BTK protein inhibitor. We synthesized and characterized glycine derived [60]fullerene using NMR, ESI-MS, and ATR-FT-IR. DLS and zeta potential were measured and high-resolution transmission electron microscopy (HRTEM) observations were performed. The chemical composition of the water-soluble fullerene nanomaterial was examined by X-ray photoelectron spectrometry. To observe aggregate formation, the cryo-TEM analysis was carried out. The docking studies and molecular dynamic simulations were performed to determine interactions between HDGF and BTK. The in vitro cytotoxicity was evaluated on RAJI and K562 blood cancer cell lines. Subsequently, we examined the induction of cell death by autophagy and apoptosis by determining the expression levels of crucial genes and caspases. We investigated the direct association of HDGF on inhibition of the BTK signalling pathway by examining changes in the calcium levels in RAJI cells after treatment. The inhibitory potential of HDGF against non-receptor tyrosine kinases was evaluated. Finally, we assessed the effects of HDGF and ibrutinib on the expression of the BTK protein and downstream signal transduction in RAJI cells following anti-IgM stimulation. Computational studies revealed that the inhibitory activity of the obtained [60]fullerene derivative is multifaceted: it hampers the BTK active site, interacting directly with the catalytic residues, rendering it inaccessible to phosphorylation, and binds to residues that form the ATP binding pocket. The anticancer activity of produced carbon nanomaterial revealed that it inhibited the BTK protein and its downstream pathways, including PLC and Akt proteins, at the cellular level. The mechanistic studies suggested the formation of autophagosomes (increased gene expression of LC3 and p62) and two caspases (caspase-3 and -9) were responsible for the activation and progression of apoptosis. These data illustrate the potential of fullerene-based BTK protein inhibitors as nanotherapeutics for blood cancer and provide helpful information to support the future development of fullerene nanomaterials as a novel class of enzyme inhibitors.

Density functional study of transition metal (Fe,Co,Ni)‐doped C60 fullerenes as 6‐thioguanine delivery system

The aim of this work is to investigate the adsorption and release mechanism of 6‐thioguanine (6TG) on transition metal (Fe,Co,Ni)‐doped C60 and C60 fullerene nanomaterials by density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) to better understand the targeted drug delivery performance of fullerene to 6TG anticancer drug. The adsorption energy, solvation energy, and related chemical properties were calculated. According to thermodynamic analysis, the interaction between 6TG drug and fullerene nanocarriers is exothermic and spontaneous. Density of state (DOS) and natural bonding orbital (NBO) analyses showed that during the adsorption process of 6TG drug on the surface of fullerene, 6TG was the charge donor and fullerene was the charge acceptor. Atoms in molecule (AIM) and independent gradient model based on Hirshfeld partition (IGMH) analyses revealed Van der Waals and hydrogen bond interactions between the 6TG drug and fullerenes. In addition, fullerenes doped with transition metals can increase the solvation effect of the 6TG drug and shorten its release time from fullerenes. These results indicate that transition metal (Fe,Co,Ni)‐doped C60 fullerene can be the promising anticancer drug delivery system for 6TG.

In Situ Cellular Localization of Nonfluorescent [60]Fullerene Nanomaterial in MCF-7 Breast Cancer Cells.

Cellular localization of carbon nanomaterials in cancer cells is essential information for better understanding their interaction with biological targets and a crucial factor for further evaluating their biological properties as nanovehicles or nanotherapeutics. Recently, increasing efforts to develop promising fullerene nanotherapeutics for cancer nanotechnology have been made. However, the main challenge regarding studying their cellular effects is the lack of effective methods for their visualization and determining their cellular fate due to the limited fluorescence of buckyball scaffolds. Herein, we developed a method for cellular localization of nonfluorescent and water-soluble fullerene nanomaterials using the in vitro click chemistry approach. First, we synthesized a triple-bonded fullerene probe (TBC60ser), which was further used as a starting material for 1,3-dipolar cycloaddition using 3-azido-7-hydroxycoumarin and sulfo-cyanine5 azide fluorophores to create fluorescent fullerene triazoles. In this work, we characterized the structurally triple-bonded [60]fullerene derivative and confirmed its high symmetry (Th) and the successful formation of fullerene triazoles by spectroscopic techniques (i.e., ultraviolet–visible, fluorescence, and Fourier transform infrared spectroscopies) and mass spectrometry. The created fluorescent fullerene triazoles were successfully localized in the MCF-7 breast cancer cell line using fluorescent microscopy. Overall, our findings demonstrate that TBC60ser localizes in the lysosomes of MCF-7 cells, with only a small affinity to mitochondria.

Perspective: Considerations for Prevention and Treatment of Dermal Exposure to Toxic Organophosphorus Compounds

The potential benefit of polyhydroxy fullerene nanomaterials in preventing and alleviating toxicities from cholinesterase-inhibiting organophosphorus toxicants is compared to other dermal protectants.

Towards water-soluble [60]fullerenes for the delivery of siRNA in a prostate cancer model

This paper presents two water-soluble fullerene nanomaterials (HexakisaminoC60 and monoglucosamineC60, which is called here JK39) that were developed and synthesized as non-viral siRNA transfection nanosystems. The developed two-step Bingel–Hirsch reaction enables the chemical modification of the fullerene scaffold with the desired bioactive fragments such as d-glucosamine while keeping the crucial positive charged ethylenediamine based malonate. The ESI–MS and 13C-NMR analyses of JK39 confirmed its high Th symmetry, while X-ray photoelectron spectroscopy revealed the presence of nitrogen and oxygen-containing C–O or C–N bonds. The efficiency of both fullerenes as siRNA vehicles was tested in vitro using the prostate cancer cell line DU145 expressing the GFP protein. The HexakisaminoC60 fullerene was an efficient siRNA transfection agent, and decreased the GFP fluorescence signal significantly in the DU145 cells. Surprisingly, the glycofullerene JK39 was inactive in the transfection experiments, probably due to its high zeta potential and the formation of an extremely stable complex with siRNA.

Interactions of a Water-Soluble Glycofullerene with Glucose Transporter 1. Analysis of the Cellular Effects on a Pancreatic Tumor Model.

In recent years, carbon nanomaterials have been intensively investigated for their possible applications in biomedical studies, especially as drug delivery vehicles. Several surface modifications can modulate the unique molecular structure of [60]fullerene derivatives, as well as their physicochemical properties. For this reason, covalent modifications that would enable a greater water solubilization of the fullerene buckyball have been rapidly investigated. The most exciting applications of fullerene nanomaterials are as drug delivery vectors, photosensitizers in photodynamic therapy (PDT), astransfection or MRI contrast agents, antimicrobials and antioxidants. From these perspectives, the glucose derivatives of [60]fullerene seem to be an interesting carbon nanomaterial for biological studies. It is well-known that cancer cells are characterized by an increased glucose uptake and it has also been previously reported that the glucose transporters (GLUTs) are overexpressed in several types of cancers, which make them attractive molecular targets for many drugs. This study explored the use of a highly water-soluble glycofullerene (called Sweet-C60) in pancreatic cancer studies. Here, we describe the PANC-1 cell proliferation, migration, metabolic activity and glycolysis rate after incubations with different concentrations of Sweet-C60. The final results did not show any influence of the Sweet-C60 on various cancer cellular events and glycolysis, suggesting that synthesized glycofullerene is a promising drug delivery vehicle for treating pancreatic cancer.

Gadofullerene inhibits the degradation of apolipoprotein B100 and boosts triglyceride transport for reversing hepatic steatosis.

Hepatic steatosis is a widespread metabolic disease characterized by excessive accumulation of triglyceride (TG) in liver. So far, effective approved drugs for hepatic steatosis are still in development, and removing the unnecessary TG from the hepatocytes is an enormous challenge. Here, we explore a promising anti-hepatic steatosis strategy by boosting hepatocellular TG transport using β-alanine-modified gadofullerene (GF-Ala) nanoparticles. We confirm that GF-Ala could reverse hepatic steatosis in oleic acid-induced hepatocytes, fructose-induced mice, and obesity-associated transgenic ob/ob mice. Observably, GF-Ala improves hepatomegaly and hepatic lipid accumulation, reduces lipid peroxidation, and repairs abnormal mitochondria. Of note, we demonstrate that GF-Ala markedly inhibits the posttranslational degradation of apolipoprotein B100 (ApoB100) and boosts hepatocellular TG transport based on their superior antioxidant property. Together, we conclude that GF-Ala could potently ameliorate hepatic TG transport and maintain hepatic metabolic homeostasis without apparent toxicity, being beneficial for treatments of hepatic steatosis and other fatty liver diseases.

Developing [60]Fullerene Nanomaterials for Better Photodynamic Treatment of Non-Melanoma Skin Cancers.

Skin cancer is the most common cancer in the U.S.A. and Europe. Its subtype, squamous skin carcinoma (SCC), if allowed to grow, has the potential to metastasize and can become deadly. Currently, carbon nanomaterials are being developed to treat cancer due to their attractive physicochemical and biological properties such as an enhanced permeability effect and their ability to produce reactive oxygen species. Here, we describe the synthesis of two water-soluble aminofullerenes (MonoaminoC60 and HexakisaminoC60), which were evaluated as novel [60]fullerene based photosentizers exhibiting anticancer properties. Moreover, the previously described neutral glycofullerene GF1 and its peracetylated lipophilic precursor MMS48 were compared with the aminofullerenes for their ability to generate reactive oxygen species and oxidize lipids. Remarkably, the generation of singlet oxygen and a superoxide radical by HexakisaminoC60 was found to be markedly elevated in the presence of bovine serum albumin and NADH, respectively. Mechanistic studies of lipid peroxidation using cholesterol as a unique reporter molecule revealed that although all four fullerene nanomaterials primarily generated singlet oxygen, superoxide anion was also formed, which suggest a mixed mechanism of action (in which Type I and Type II photochemistry is involved). The [60]fullerene derivative HexakisaminoC60 was also studied for its phototoxicity in squamous skin cancer cell line (A431) using the MTT test and propidium iodide staining.

Nanoarchitectonics of Nanoporous Carbon Materials in Supercapacitors Applications.

High surface area and large pore volume carbon materials having hierarchical nanoporous structure are required in high performance supercapacitors. Such nanoporous carbon materials can be fabricated from organic precursors with high carbon content, such as synthetic biomass or agricultural wastes containing cellulose, hemicellulose, and lignin. Using recently developed unique concept of materials nanoarchitectonics, high performance porous carbons with controllable surface area, pore size distribution, and hierarchy in nanoporous structure can be fabricated. In this review, we will overview the recent trends and advancements on the synthetic methods for the production of hierarchical porous carbons with one- to three-dimensional network structure with superior performance in supercapacitors applications. We highlight the promising scope of accessing nanoporous graphitic carbon materials from: (i) direct conversion of single crystalline self-assembled fullerene nanomaterials and metal organic frameworks, (ii) hard- and soft-templating routes, and (iii) the direct carbonization and/or activation of biomass or agricultural wastes as non-templating routes. We discuss the appealing points of the different synthetic carbon sources and natural precursor raw−materials derived nanoporous carbon materials in supercapacitors applications.

Possible role of C60 fullerene in the induction of reproductive toxicity in the freshwater fish, Anabas testudineus (Bloch, 1792).

In recent years, the impact of ultrafine nanomaterials on the aquatic organisms and their ecosystems contributed much concern due to their abundance in environment. Several toxicity studies have reported that nanoparticles induced reproductive stress and resulted in reproductive impairment of fishes. The present study was aimed to investigate the stress-induced toxicity of C60 fullerene nanomaterial on various reproductive parameters of the freshwater fish, Anabas testudineus. Fish were exposed to two sublethal concentrations of fullerene C60, one-tenth (5mg/L) and one-fifth (10mg/L) of LC50-96h, for 4, 7, 15, 30, and 60-day durations. At the end of exposure period, the activities of steroidogenic enzymes, 3β-, and 17β-hydroxysteroid dehydrogenase decreased in the testis and ovary thereby indicated that the nanomaterial affected gonadal steroidogenesis. The level of serum testosterone decreased significantly (p < 0.05) in male whereas the level of estradiol showed significant (p < 0.05) reduction in female fish with significant (p< 0.05) increase in the level of serum cortisol in both sexes in concentration- and time-dependent manner. The analysis of the levels of alkali-labile phosphates, plasma calcium, and total protein showed significant (p < 0.05) reduction in female fish without significant changes in male fish, and this could be due to the antiestrogenic action of fullerene C60 nanomaterial. The activity of aromatase enzyme decreased significantly (p < 0.05) in the ovary and brain of female fish, and the decline in the enzyme activity was prominent only in the brain tissue of male fish. The present results suggested that the stress-induced by fullerene C60 exposure provoked reproductive toxicity in the fish, Anabas testudineus.

A [60]fullerene nanoconjugate with gemcitabine: synthesis, biophysical properties and biological evaluation for treating pancreatic cancer

BackgroundThe first-line chemotherapy drug that is used to treat pancreatic ductal adenocarcinoma is gemcitabine. Unfortunately, its effectiveness is hampered by its chemo-resistance, low vascularization and drug biodistribution limitations in the tumor microenvironment. Novel nanotherapeutics must be developed in order to improve the prognosis for patients with pancreatic cancer.ResultsWe developed a synthetic methodology for obtaining a water-soluble nanoconjugate of a [60]fullerene-glycine derivative with the FDA-approved drug gemcitabine (nanoC60GEM). The proposed synthetic protocol enables a highly water-soluble [60]fullerene-glycine derivative (6) to be obtained, which was next successfully conjugated with gemcitabine using the EDCI/NHS carbodiimide protocol. The desired nanoconjugate was characterized using mass spectrometry and DLS, IR and XPS techniques. The photogeneration of singlet oxygen and the superoxide anion radical were studied by measuring 1O2 near-infrared luminescence at 1270 nm, followed by spin trapping of the DMPO adducts by EPR spectroscopy. The biological assays that were performed indicate that there is an inhibition of the cell cycle in the S phase and the induction of apoptosis by nanoC60GEM.ConclusionIn this paper, we present a robust approach for synthesizing a highly water-soluble [60]fullerene nanoconjugate with gemcitabine. The performed biological assays on pancreatic cancer cell lines demonstrated cytotoxic effects of nanoC60GEM, which were enhanced by the generation of reactive oxygen species after blue LED irradiation of synthesized fullerene nanomaterial.

Dependence of the surface-assisted fullerene-based complex structure on the template molecule design

Fullerene derivatives as a kind of star carbon materials have received intense investigation because of their three-dimensional shape, anisotropic electron mobility, and high electron affinity. Indeed, the cutting-edge developments of fullerene nanomaterials have had a tremendous impact on a wide range of applications, such as organic solar cells, field effect transistors, and photodetectors. To explore their full potential applications, research into fullerene-based multilevel nanostructures relying on hierarchical interactions from bottom to top is rapidly expanding. It is of great theoretical and practical significance to prepare multilevel fullerene nanostructures with structural and properties controlled by optimizing the influencing factors. This review would offer several aspects including the chemical structures of organic molecules and the nanostructures of the organic molecules and fullerene-organic complexes. Whether monolayers or multilayers, fullerene molecules tend to fall into a space of suitable size, in which the located positions are affected by the intermolecular interactions. For the covered surfaces, fullerenes are more likely to approach the electron-withdrawing units through the donor–acceptor and charge transfer interaction. Through the implementation of this review, an exhaustive analysis on the chemical modification, including the molecular backbone and substituents, preformed network synergies, and adsorption sites is presented. In addition, the relationship between the molecules and structures that illustrates the importance of the molecular design for the controlled fullerenes hybrid nanostructures can be further understood based on the results of the joined experimental and computational investigations.

Uptake and Transfer of 13C-Fullerenols from Scenedesmus obliquus to Daphnia magna in an Aquatic Environment

Fullerenol, a water-soluble polyhydroxylated fullerene nanomaterial, enters aquatic organisms and ecosystems through different ingestion exposures and may pose environmental risks. The study of their uptake routes and transfer in aquatic systems is scarce. Herein, we quantitatively investigated the aquatic uptake and transfer of 13C-fullerenols from Scenedesmus obliquus to Daphnia magna using 13C-skeleton-labeling techniques. The bioaccumulation and depuration of fullerenol in Daphnia magna increased with exposure doses and time, reaching steady state within 16 h in aqueous and feeding-affected aqueous routes. The capacity of Daphnia magna to ingest fullerenol via the aqueous route was much higher than that via the dietary route. From the aqueous to feeding-affected aqueous, the kinetic analysis demonstrated the bioaccumulation factors decreases, which revealed that algae suppressed Daphnia magna uptake of fullerenols. The aqueous route was the primary fullerenols ingestion pathway for Daphnia magna. Kinetic analysis of the accumulation and transfer in Daphnia magna via the dietary route indicated low transfer efficiency of fullerenol along the Scenedesmus obliquus-Daphnia magna food chain. Using stable isotope labeling techniques, these quantitative data revealed that carbon nanomaterials underwent complex aquatic accumulation and transfer from primary producers to secondary consumers and algae inhibited their transfer in food chains.

Toxicity of functionalized fullerene and fullerene synthesis chemicals

Fullerene is one of the most studied carbon-based nanoparticles due to its unique structure and potential for diverse applications. This study focuses on toxicological effects of two fullerene nanomaterials, contributing to ecological as well as human risk assessment strategies. The biological responses from two basic fullerene materials, aqueous-nanoC60 and alkaline-synthesized fullerenol, were examined using four model organisms. Bioassays were conducted on bacteria (Pseudomonas aeruginosa and Staphylococcus aureus) to determine population impacts and to assess mechanisms of cellular effects for both Gram-negative and Gram-positive species. LC50 of aqu-nC60 stirred for 28 days for P. aeruginosa was estimated to be 1336 mg/L; however, toxicity of the same aqu-nC60 preparation for S. aureus was insignificant. Freshwater green algae Raphidocelus subcapitata and invertebrate Ceriodaphnia dubia were exposed to 28-day stirred aqu-nC60 with no significant toxicological impact. Aqu-nC60 stirred for 14 days bore no toxicity within two orders of magnitude greater than the highest concentration administered. LC50 for organisms exposed to alkaline-synthesized fullerenol prepared in the laboratory was 2409 mg/L for P. aeruginosa with no determinable toxicity to S. aureus, and 1462 mg/L and 45.2 mg/L for R. subcapitata and C. dubia, respectively. Toxicity thresholds for commercially-prepared fullerenol were lower for all species, an impact attributed to the presence of impurities. Mechanistic analysis of membrane damage on bacteria by laboratory-prepared fullerenol indicated necrotic and apoptotic responses with and without photoactivation. Toxicological responses from fullerenol synthesis by-products were only determinable for C. dubia with effects attributable to impurities.

Synthesis And Evaluation Of Swelling Characteristics Of Fullerene (C60) Containing Cross-linked Poly(2-hydroxyethyl Methacrylate) Hydrogels

Fullerene (C60) containing cross-linked poly (2-hydroxyethyl methacrylate) polymers (CFPH) with varying C60 content were synthesized by free radical polymerization. The fullerene content in the cross-linked polymers was determined by TGA analysis. The swelling properties of these fullerene containing hydrogels (CFPH) were studied in distilled water (pH=7.2) at room temperature (25 o C) and compared to the corresponding hydrogel without fullerene (CPHEMA). The equilibrium swelling ratio is lower for the fullerene containing hydrogels (54.68% and 40.0% for hydrogels having 6.0 wt% and 18.0 wt% fullerene respectively) due to the presence of hydrophobic fullerene moieties inside the hydrogels than that of the hydrogel (68.75%) without fullerene. The hydrophobic fullerene nanomaterials acting as inherent nanofillers obstruct the path of water permeation inside the polymers thereby taking more time to achieve equilibrium swelling for fullerene containing hydrogels than that of the hydrogel without fullerene. The kinetics of swelling behavior of such fullerene containing cross-linked hydrogels (CFPH) was observed to follow Fickian behavior. Increase of temperature and ionic strength of the medium decrease the water uptake capacity of the fullerene containing cross-linked hydrogels. Fullerene containing hydrogels may be useful in drug delivery system and other biomedical applications. Copyright © 2014 VBRI press.