Design and synthesis of highly fluorescent and stable fullerene nanoparticles as probes for folic acid detection and targeted cancer cell imaging.

Rational design and construction of fullerene derivatives play significant roles in the development of applications for sensing, marking and imaging in biomedical fields. In the present work, a novel type of C60 fluorescent nanoparticle (C60 FNP) was synthesized by a combination of thiol-ene chemistry and modification with folic acid (FA). The as-prepared C60 FNPs exhibited intense blue luminescence with a relatively high quantum yield of 26%, which is higher than that of any other reported fluorescent fullerene-based nanomaterial. Moreover, they revealed superior photobleaching resistance under constant UV lamp illumination for 5 h and excellent photostablity after 9 months of storage in water. Due to the mutual hydrogen bond interaction, the obtained C60 FNPs were capable of acting as a sensitive and specific probe for FA detection and quantification, with a liner range of 0 to 80 µM and a detection limit of 0.24 µM. Satisfactory recoveries (95.4%-105.2%) were obtained from a series of actual samples, further confirming the feasibility of this nanoprobe. Additionally, taking advantage of the FA moiety, the C60 FNPs had easy access to penetrate into cancer cells with higher expression levels of folate receptors, thereby achieving the function of targeted cellular imaging.

Visualization of the tissue distribution of fullerenols in zebrafish (Danio rerio) using imaging mass spectrometry.

With the wide application of fullerenols in biomedicine, their environmental exposure risks and toxicity to organisms have been extensively studied. However, there is still a lack of knowledge about the distribution of fullerenols in organisms as an important aspect of their mechanism of toxicity. High-resolution matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) is an emerging technology for researching the distribution of molecules in biological tissue samples. Using this high-resolution technique, we map the distribution of fullerenols in zebrafish tissues, and the results suggest that fullerenols enter the gill, intestine, and muscle tissues and even permeate the blood-brain barrier, reaching the brain of zebrafish after aquatic exposure. Moreover, from the MS images of fullerenols, the distribution amount of fullerenols is highest in the gill, followed by that in the intestine and the small amount in muscle and brain tissues. As an emerging environmental pollutant, the establishment of this research method will provide a new method for the study of the environmental toxicity of carbon nanomaterials. Our results also indicated that this high-resolution imaging method could be applied to explore the mechanism of interaction between carbon nanomaterials and biological systems at the cellular level in the future.

Water-Soluble Fullerenol C60(OH)36 toward Effective Anti-Air Pollution Induced by Urban Particulate Matter in HaCaT Cell.

Particulate matter (PM), a widespread air pollutant, consists of a complex mixture of solid and liquid particles suspended in air. Many diseases have been linked to PM exposure, which induces an imbalance in reactive oxygen species (ROS) generated in cells, and might result in skin diseases (such as aging and atopic dermatitis). New techniques involving nanomedicine and nano-delivery systems are being rapidly developed in the medicinal field. Fullerene, a kind of nanomaterial, acts as a super radical scavenger. Lower water solubility levels limit the bio-applications of fullerene. Hence, to improve the water solubility of fullerene, while retaining its radical scavenger functions, a fullerene derivative, fullerenol C60(OH)36, was synthesized, to examine its biofunctions in PM-exposed human keratinocyte (HaCaT) cells. The PM-induced increase in ROS levels and expression of phosphorylated mitogen-activated protein kinase and Akt could be inhibited via fullerenol pre-treatment. Furthermore, the expression of inflammation-related proteins, cyclooxygenase-2, heme oxygenase-1, and prostaglandin E2 was also suppressed. Fullerenol could preserve the impaired state of skin barrier proteins (filaggrin, involucrin, repetin, and loricrin), which was attributable to PM exposure. These results suggest that fullerenol could act against PM-induced cytotoxicity via ROS scavenging and anti-inflammatory mechanisms, and the maintenance of expression of barrier proteins, and is a potential candidate compound for the treatment of skin diseases.

Fullerene Radiolysis in Astrophysical Ice Analogs: A Mass Spectrometric Study of the Products.

The γ-radiolysis of fullerenes (C60 and C70) was performed to investigate the role of fullerenes as a carbon source in building organic molecules in astrophysical ice analog media. Mass spectrometric analyses and the sequential collision-induced dissociation processes enabled us to determine the plausible chemical structure of new products originated during γ-irradiation of fullerenes. The radiolytic products are grouped into six principal compound families. We assessed the relative yield, as percentage, for each new radiolytic compound, and designed the reaction schemes that lead to γ-irradiation products. The reactions start with the formation of primary radicals due to the radiolysis of solvents that react with the fullerenes' structures, forming fullerene radical adducts. The fate of these fullerene radical adducts depends on two factors: (i) the nature of radicals formed by irradiation of solvents and consequently by their ability to give secondary reactions, (ii) whether the onset of thermalization energy processes occurs or does not occur. Here, we present the results regarding the fragmentation processes that lead to functionalized carbonaceous chains characterized by lower molecular weight. We identify the chemical nature of functionalized chain products, propose the reaction schemes, and quantify their relative yields.

Polyvalent Nanoobjects for Precision Diagnostics.

As our ability to synthesize and modify nanoobjects has improved, efforts to explore nanotechnology for diagnostic purposes have gained momentum. The variety of nanoobjects, especially those with polyvalent properties, displays a wide range of practical and unique properties well suited for applications in various diagnostics. This review briefly covers the broad scope of multivalent nanoobjects and their use in diagnostics, ranging from ex vivo assays and biosensors to in vivo imaging. The nanoobjects discussed here include silica nanoparticles, gold nanoparticles, quantum dots, carbon dots, fullerenes, polymers, dendrimers, liposomes, nanowires, and nanotubes. In this review, we describe recent reports of novel applications of these various nanoobjects, particularly as polyvalent entities designed for diagnostics.

Adsorption of Celecoxib on B12N12 fullerene: Spectroscopic and DFT/TD-DFT study.

In this study, we evaluated the effect of the Celecoxib (CXB) adsorption on the electronic and optical properties of B12N12 fullerene by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations with the M06-2X functional and the 6-311+G** basis set. The calculated adsorption energies of CXB with the B12N12 fullerene was evaluated at T = 298.15 K in the vacuum and solvent (water) environments with the M06-2X functional. UV absorption and IR spectra were calculated and studied in order to identify the most important changes happening as a consequence of interactions between CXB and B12N12 fullerene. The results revealed that the adsorption of the CXB molecule from its NH2 head on the B12N12 is more favorable than those of the SO2 and NH groups in the gas and solvent environments. It is anticipated that the applied B12N12 fullerene could be suitable as a biomedical carrier for the delivery of CXB drug.

Fullerene C60 in Atmospheric Aerosol and Its Relationship to Combustion Processes.

Fullerenes are emerging pollutants, and it is essential to determine and quantify these compounds to assess environmental risk and environmental flows. The goal of this work was to determine the fullerene C60 emission levels in the atmospheric aerosol and their relationship with combustion processes. To measure the concentration, a fullerene C60 extraction method with toluene was optimized in air samples using ultrasound, followed by analysis using high-pressure, liquid chromatography-diode array detector-mass spectrometry. This method has been applied to outdoor and indoor environmental samples collected in different places in Vitoria-Gasteiz (Spain), with diverse environmental characteristics, as well as at the exhaust outlets of different vehicles with and without catalytic converters. The maximum concentration of fullerene C60 present in the outdoor samples was 2.27 pg/m3, and the maximum concentration was 10.50 pg/m3 in indoor environments. The air samples collected at the exhaust outlets of vehicles without catalytic converters showed fullerene C60 concentrations above 170 pg/m3, while in the case of vehicles with catalytic converters, the detected concentration of fullerene C60 was lower than the limit of quantification.

First determination of fullerenes in the Austrian market and environment: quantitative analysis and assessment.

This study forms the first report on analyzing fullerenes in the Austrian environment and cosmetic products available on the Austrian market. We developed, optimized, and validated a novel method for the analysis of C60 and C70 fullerenes and N-methylfulleropyrrolidine C60 (NMFP) for measuring sensitivities in the low nanograms per liter range in order to prove their presence in the environment (12 wastewater- and 12 sewage sludge samples) and in 11 selected fullerene-containing cosmetic products from three different brands. The optimized method relies on a liquid-liquid extraction (LLE) or solid-liquid extraction (SLE) and, for the first time, introduced the Carrez-clarification, followed by liquid chromatography (LC) and coupled to a hybrid triple quadrupole mass spectrometry (MS) quantification. The total variability of the new established LC-MS/MS method based on all the tested matrices was below 10%. We found recoveries generally higher than 70% for both tap water and surface water. The limits of quantitation (LOQ) for the wastewater samples were measured to be from 0.8 to 1.6 ng/L, for the sewage sludge samples, from 1.4 to 2.6 ng/g DM (drymass), and for the cosmetic samples from 0.2 to 0.4 ng/g. None of the analyzed samples of wastewater or sewage sludge samples contained fullerenes. But in 70% of the tested cosmetics, fullerene concentrations between 10 and 340 ng/g were detected. These values were much lower than concentrations causing toxicity in water animals.

Targeted gadofullerene for sensitive magnetic resonance imaging and risk-stratification of breast cancer.

Molecular imaging of cancer biomarkers is critical for non-invasive accurate cancer detection and risk-stratification in precision healthcare. A peptide-targeted tri-gadolinium nitride metallofullerene, ZD2-Gd3N@C80, is synthesised for sensitive molecular magnetic resonance imaging of extradomain-B fibronectin in aggressive tumours. ZD2-Gd3N@C80 has superior r 1 and r 2 relaxivities of 223.8 and 344.7 mM-1 s-1 (1.5 T), respectively. It generates prominent contrast enhancement in aggressive MDA-MB-231 triple negative breast cancer in mice at a low dose (1.7 µmol kg-1, 1 T), but not in oestrogen receptor-positive MCF-7 tumours. Strong tumour contrast enhancement is consistently observed in other triple negative breast cancer models, but not in low-risk slow-growing tumours. The dose of the contrast agent for effective molecular MRI is only slightly lower than that of ZD2-Cy5.5 (0.5 µmol kg-1) in fluorescence imaging. These results demonstrate that high-sensitivity molecular magnetic resonance imaging with ZD2-Gd3N@C80 may provide accurate detection and risk-stratification of high-risk tumours for precision healthcare of breast cancer.Molecular MRI is a powerful clinical tool for non-invasive detection of cancer biomarkers. Here, the authors develop a targeted peptide gadofullerene contrast agent that can sensitively distinguish between breast cancers of different aggressiveness.

Fate of radiolabeled C60 fullerenes in aged soils.

Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of (14C)-C60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of 14C across solvents and matrices were used to provide insights on C60 behavior. In most samples, 14C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable 14C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed 14C distribution, i.e. retention and potential transformation of C60, were discussed. Over-all, results suggest that environmental exposure to C60 and potentially transformed C60 species, as a result of their release from soils, is likely to be low.

Is there evidence for man-made nanoparticles in the Dutch environment?

Only very limited information is available on measured environmental concentrations of nanoparticles. In this study, several environmental compartments in The Netherlands were probed for the presence of nanoparticles. Different types of water were screened for the presence of inorganic (Ag, Au, TiO2) and organic nanoparticles (C60, C70, [6,6]-phenyl-C61-butyric acid octyl ester, [6,6]-phenyl-C61-butyric acid butyl ester, [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-bis-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C71-butyric acid methyl ester, [6,6]-thienyl-C61-butyric acid methyl ester). Air samples were analysed for the presence of nanoparticulate Mo, Ag, Ce, W, Pd, Pt, Rh, Zn, Ti, Si, B as well as Fe and Cu. ICP-MS, Orbitrap-HRMS, SEM and EDX were used for this survey. Water samples included dune and bank filtrates, surface waters and ground waters as well as influents, effluents and sludge of sewage treatment plants (STPs), and surface waters collected near airports and harbours. Air samples included both urban and rural samples. C60 was detected in air, sewage treatment plants, influents, effluents and sludge, but in no other aqueous samples despite the low detection limit of 0.1ng/L. C70 and functionalised fullerenes were not detected at all. In STP sludge and influent the occurrence of Ag and Au nanoparticles was verified by SEM/EDX and ICP-MS. In air up to about 25m% of certain metals was found in the nanosize fraction. Overall, between 1 and 6% of the total mass from metals in the air samples was found in the size fraction <100nm.

Analysis of fullerenes in soils samples collected in The Netherlands.

Fullerenes are carbon based nanoparticles that may enter the environment as a consequence of both natural processes and human activities. Although little is known about the presence of these chemicals in the environment, recent studies suggested that soil may act as a sink. The aim of the present work was to investigate the presence of fullerenes in soils collected in The Netherlands. Samples (n = 91) were taken from 6 locations and analyzed using a new developed LC-QTOF-MS method. The locations included highly trafficked and industrialized as well as urban and natural areas. In general, C60 was the most abundant fullerene found in the environment, detected in almost a half of the samples and at concentrations in the range of ng/kg. Other fullerenes such as C70 and an unknown structure containing a C60 cage were detected to a lower extent. The highest concentrations were found in the proximity of combustion sites such as a coal power plant and an incinerator, suggesting that the nanoparticles were unintentionally produced during combustions processes and reached the soil through atmospheric deposition. Consistent with other recent studies, these results show that fullerenes are widely present in the environment and that the main route for their entrance may be due to human activities. These data will be helpful in the understanding of the distribution of fullerenes in the environment and for the study of their behavior and fate in soil.

Nanominerals, fullerene aggregates, and hazardous elements in coal and coal combustion-generated aerosols: An environmental and toxicological assessment.

Studies on coal-derived nanoparticles as well as nano-minerals are important in the context of the human health and the environment. The coal combustion-generated aerosols also affect human health and environmental quality aspects in any coal-fired station. In this study, the feed coals and their combustion-generated aerosols from coal-fired boilers of two tea industry facilities were investigated for the presence of nanoparticles/nano minerals, fullerene aggregates, and potentially hazardous elements (PHEs). The samples were characterized by using X-ray diffraction (XRD), Time-of-flight secondary ion mass spectroscopy (TOF-SIMS), High resolution-transmission electron microscopy/energy dispersive spectroscopy (HR-TEM/EDS) and Ultra Violet-visible spectroscopy (UV-Vis) to know their extent of environmental risks to the human health when present in coals and aerosols. The feed coals contain mainly clay minerals, whilst glass fragments, spinel, quartz, and other minerals occur in lesser quantities. The PM samples contain potentially hazardous elements (PHEs) like As, Pb, Cd and Hg. Enrichment factor of the trace elements in particulate matters (PMs) was calculated to determine their sources. The aerosol samples were also found to contain nanomaterials and ultrafine particles. The fullerene aggregates along with potentially hazardous elements were also detected in the aerosol samples. The cytotoxicity studies on the coal combustion-generated PM samples show their potential risk to the human health. This detailed investigation on the inter-relationship between the feed coals and their aerosol chemistry will be useful for understanding the extent of environmental hazards and related human health risk.

Bioavailability of classical and novel flame retardants: Effect of fullerene presence.

To understand the behavior of some emerging flame retardants (FRs) in the environment, a nonexhaustive extraction using Tenax was applied to study their behavior in aquatic ecosystems. Desorption of 8 polybrominated diphenyl ethers (PBDEs), 8 methoxylated PBDEs, 3 emerging brominated FRs and 6 halogenated norbornenes from sediments spiked in the laboratory was studied. Results showed that emerging FRs have a similar bioavailability than that of legacy FRs, already banned. In addition, some parameters such as sediment total organic carbon (TOC), aging or nanomaterial (NMs) presence in the sediment were modified in order to study their effects on the bioavailability of FRs. Bioavailability increases with a diminution of sediment TOC, while diminishes with an increase of aging. The study of effect of NM presence was performed at three different pH (acidic, neutral and basic), and for the three scenarios, FR bioavailability decreased with NM presence. The retention of pollutants in the sediment seems to be favoured by NM presence, minimizing their impact on living organisms.

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant.

Surfactant complexation may have significant effects on the environmental behavior of nano-particles. In order to understand the ecological exposure of nano-materials, it is important to determine the stability and mobility of surfactant-complexed nano-materials in aqueous systems. In this study, the aggregation and transport of C60 complexed by the surfactant sodium dodecyl benzene sulfonate (SDBS) were investigated. It was found that SDBS-complexed C60 had a ζ-potential of -49.5 mV under near-neutral pH conditions and remained stable during an aging period of 15 days. It had a critical coagulation concentration of 550 mmol/L for NaCl, which was higher than common natural colloids and many kinds of raw nano-materials, and was comparable to those of many kinds of surface-modified nano-materials. SDBS enhanced the stability of C60 colloid; however, at the same time, it also enhanced the colloidal particle aggregation rate. Much higher mobility was found for SDBS-complexed C60 than C60 colloid. Increase in ionic strength, Ca(2+) concentration or Al(3+) concentration decreased the mobility. In general, SDBS-complexed C60 had high stability and mobility.

Mass Spectrometry as a Preparative Tool for the Surface Science of Large Molecules.

Measuring and understanding the complexity that arises when nanostructures interact with their environment are one of the major current challenges of nanoscale science and technology. High-resolution microscopy methods such as scanning probe microscopy have the capacity to investigate nanoscale systems with ultimate precision, for which, however, atomic scale precise preparation methods of surface science are a necessity. Preparative mass spectrometry (pMS), defined as the controlled deposition of m/z filtered ion beams, with soft ionization sources links the world of large, biological molecules and surface science, enabling atomic scale chemical control of molecular deposition in ultrahigh vacuum (UHV). Here we explore the application of high-resolution scanning probe microscopy and spectroscopy to the characterization of structure and properties of large molecules. We introduce the fundamental principles of the combined experiments electrospray ion beam deposition and scanning tunneling microscopy. Examples for the deposition and investigation of single particles, for layer and film growth, and for the investigation of electronic properties of individual nonvolatile molecules show that state-of-the-art pMS technology provides a platform analog to thermal evaporation in conventional molecular beam epitaxy. Additionally, it offers additional, unique features due to the use of charged polyatomic particles. This new field is an enormous sandbox for novel molecular materials research and demands the development of advanced molecular ion beam technology.

A method for the determination of fullerenes in soil and sediment matrices using ultra-high performance liquid chromatography coupled with heated electrospray quadrupole time of flight mass spectrometry.

The increasing production of fullerenes likely means a release of these chemicals in the environment. Since soils and sediments are expected to act as a sink, analytical tools are needed to assess the presence of fullerenes in these matrices. In the present work, a method was developed for the determination of fullerenes at environmental relevant levels employing Ultra High Performance Liquid Chromatograph coupled with High Resolution Mass Spectrometry (UHPLC-HRMS). Chromatographic separation was achieved with a core-shell biphenyl stationary phase that provided fast analysis with complete baseline separation. Ion Booster Electro Spray Ionization (IB-ESI) resulted in higher ionization efficiency and was much less susceptible to adduct formation in comparison with standard ESI, whereas Quadrupole Time of Flight (QTOF) MS granted high resolution mass spectra used for accurate identification. The Instrumental method limits of detection (ILoD) and quantification (ILoQ) were 6 and 20 fg, respectively, for C60 and 12 and 39 fg, respectively, for C70. Matrix effects related to co-extractants were systematically investigated in soil and sediments extracts through standard addition method (SAM) and monitoring the signal response during the chromatographic run of these samples. Consequently, minor chromatographic modifications were necessary for the analysis of matrices with high organic carbon content. The method limit of detection (MLoD)ranged from 84 pg/kg to 335 pg/kg, whereas limit of quantification (MLoQ) ranged from 279 pg/kg to 1.1 ng/kg. Furthermore, the method was successfully applied for the analysis of functionalized fullerenes (i.e. methanofullerenes). To the best of our knowledge, this is the first analytical method for the analysis of fullerenes in soils and sediments that employ core-shell biphenyl stationary phase as well as IB-ESI-QTOF MS hyphenated with UHPLC.

Removal of aqueous nC60 fullerene from water by low pressure membrane filtration.

The potential environmental and health risks of engineered nanoparticles such as buckminsterfullerene C60 in water require their removal during the production of drinking water. We present a study focusing on (i) the removal mechanism and (ii) the elucidation of the role of the membrane pore size during removal of nC60 fullerene nanoparticle suspensions in dead-end microfiltration and ultrafiltration mimicking separation in real industrial water treatment plants. Membranes were selected with pore sizes ranging from 18 nm to 500 nm to determine the significance of the nC60 to membrane pore size ratio and the adsorption affinity between nC60 and membrane material during filtration. Experiments were carried out with a dead-end bench-scale system operated at constant flux conditions including a hydraulic backwash cleaning procedure. nC60 nanoparticles can be efficiently removed by low pressure membrane technology with smaller and, unexpectedly, also by mostly similar or larger pores than the particle size, although the nC60 filtration behaviour appeared to be different. The nC60 size to membrane pore size ratio and the ratio of the cake-layer deposition resistance to the clean membrane resistance, both play an important role on the nC60 filtration behaviour and on the efficiency of the backwash procedure recovering the initial membrane filtration conditions. These results become specifically significant in the context of drinking water production, for which they provide relevant information for an accurate selection between membrane processes and operational parameters for the removal of nC60 in the drinking water treatment.

C60 fullerenes from combustion of common fuels.

Releases of C60 fullerenes to the environment will increase with the growth of nanotechnology. Assessing the potential risks of manufactured C60 requires an understanding of how its prevalence in the environment compares to that of natural and incidental C60. This work describes the characterization of incidental C60 present in aerosols generated by combustion of five common fuels: coal, firewood, diesel, gasoline, and propane. C60 was found in exhaust generated by all five fuels; the highest concentrations in terms of mass of C60 per mass of particulate matter were associated with diesel and coal. Individual aerosols from these combustion processes were examined by transmission electron microscopy. No relationship was found between C60 content and either the separation of graphitic layers (lamellae) within the particles, nor the curvature of those lamellae. Estimated global emissions of incidental C60 to the atmosphere from coal and diesel combustion range from 1.6 to 6.3 t yr(-1), depending upon combustion conditions. These emissions may be similar in magnitude to the total amount of manufactured C60 produced on an annual basis. Consequent loading of incidental C60 to the environment may be several orders of magnitude higher than has previously been modeled for manufactured C60.

Probabilistic environmental risk assessment of five nanomaterials (nano-TiO2, nano-Ag, nano-ZnO, CNT, and fullerenes).

The environmental risks of five engineered nanomaterials (nano-TiO2, nano-Ag, nano-ZnO, CNT, and fullerenes) were quantified in water, soils, and sediments using probabilistic Species Sensitivity Distributions (pSSDs) and probabilistic predicted environmental concentrations (PECs). For water and soil, enough ecotoxicological endpoints were found for a full risk characterization (between 17 and 73 data points per nanomaterial for water and between 4 and 20 for soil) whereas for sediments, the data availability was not sufficient. Predicted No Effect Concentrations (PNECs) were obtained from the pSSD and used to calculate risk characterization ratios (PEC/PNEC). For most materials and environmental compartments, exposure and effect concentrations were separated by several orders of magnitude. Nano-ZnO in freshwaters and nano-TiO2 in soils were the combinations where the risk characterization ratio was closest to one, meaning that these are compartment/ENM combinations to be studied in more depth with the highest priority. The probabilistic risk quantification allows us to consider the large variability of observed effects in different ecotoxicological studies and the uncertainty in modeled exposure concentrations. The risk characterization results presented in this work allows for a more focused investigation of environmental risks of nanomaterials by consideration of material/compartment combinations where the highest probability for effects with predicted environmental concentrations is likely.