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We report about the growth of carbon nanotubes, carbon microfibers and other forms of carbon on uncoated silicon and glass substrates, obtained by evaporating either a solid carbon precursor such as camphor or a liquid one such as cyclohexanol. The latter is a cyclic alcohol never used before in this field. The process of synthesis involves the coevaporation of the carbon precursor and ferrocene, used as the catalyst source, in nitrogen atmosphere. The morphology and structure of the samples grown at various substrate temperatures were characterized by Raman and FT-IR spectroscopy, HR-TEM and SEM analysis. At a substrate temperature of about 650 °C a ‘carpet’ of vertically oriented nanotubes, with spare signs of other form of carbons, is obtained on silicon substrate, whereas a disordered carbon nanotubes structure and other carbon form are grown on glass substrates. The results demonstrate the ability of this method to grow carbon nanotubes on uncoated glass substrates.

Carbon nanotubes have remarkable mechanical, electronic and electrochemical properties, but the full potential for application will be realized only if the growth of high quantity and quality carbon nanotubes can be optimized and well controlled. In this study, carbon nanotubes have been successfully grown on fused quartz rods by a novel open-air laser-induced chemical vapor deposition (LCVD) technique with gold palladium nanoparticles as catalyst material. In this LCVD technique, a curtain of inert nitrogen gas was used to shield the deposition zone from the surrounding environment and allows the growth of the nanotubes to occur under open-air conditions. A 35-W continuous CO 2 laser was used as a heat source to induce a local temperature rise on the substrate surface covered with metal nanoparticles, subsequently resulting in deposition of multi-wall carbon nanotubes. The carbon nanotubes deposited in this study are derived from a precursor mixture that consists of propane and hydrogen, and are in tangled form with different diameters (10–250 nm) and structures. Raman spectroscopy, transmission and scanning electron microscopy are used to investigate the microstructure and composition of the carbon nanotubes.

Single-wall carbon nanohorns (SWNHs) with dahlia flowerlike structures were treated with H2SO4 and H2O2/H2SO4 mixture. The SWNH samples before and after acid treatment were characterized using a transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, temperature-programmed desorption (TPD), and N2 adsorption at 77 K. According to TEM and SEM observation, the SWNH bundles were coalesced after H2SO4 and H2O2/H2SO4 treatments, growing up to the bundle size of several micrometers. The Raman spectra provided evidence that the H2O2/H2SO4 treatment leads to intercalation of the H2SO4 molecule into interstitial spaces of individual SWNHs as well as defect formation by oxidation reaction. The H2O2/H2SO4 treatment also altered markedly the N2 adsorption isotherms of SWNH from type II to type I, accompanied with an enhanced N2 adsorption uptake at low relative pressure due to the development of microporosity. Heat treatment at 873 K on H2O2/H2SO4-treated SWNHs additionally inc...

Since their discovery in 1991, carbon nanotubes have been intensively studied, and a number of new applications have been identified. Applications range from nanoelectronics to hydrogen absorption for battery electrodes and fuel cells. Because of their high electrical conductivity and strength, high sensitivity atomic force microscopes already use carbon nanotubes for their tips, and carbon nanostructures are also used as electron beam emitters for medical and scientific equipment. Electron emission is directly correlated with the work function and the ionization potential of carbon nanotubes. Gaussian 98 software was used to perform theoretical quantum calculations on a limited set of HyperChem 5.01 simulated metallic single-wall carbon nanotubes. These initial sets of calculations show that bandgaps and work functions of these small carbon nanostructures are dependent upon the diameter of the tubes, and to a lesser degree so is the ionization potential. In addition, we demonstrate how the manufacturing methods can directly affect the diameter of the nanotubes produced, and therefore directly influence the electrical properties of the nanotubes.

To extend the application fields of single-wall carbon nanotubes (SWNTs) and single-wall carbon nanohorns (SWNHs), their chemical modification is essential. Since their graphene-sheet-based structures are chemically robust, only the edges of the graphene sheets, more specifically the oxygen-containing functional groups at hole edges, are useful sites for chemical modification. However, not much is known about the hole-edges, so the phenomenon reported here, that the hole edges easily react with conventional reagents, was previously unknown. We observed a lowering of the combustion temperature of SWNTs and SWNHs immersed in water; this lowering was induced as a result of the hydrolysis of oxygen-containing functional groups (anhydrides and/or lactones) at the hole edges. We also found that the reactivity of hole edges can be easily controlled through an appropriate choice of solvents. We believe that this study is helpful to our understanding of hole-edge chemistry and will help to enable the production of...

Single-wall carbon nanohorn (SWNH) particles were generated by simple pulsed arc discharge between pure carbon rods in the atmospheric pressure of air. Purity of SWNHs was reached higher than 90%, and the heating in dry air at 500 °C was useful for removal of amorphous carbon. The mean size of SWNH particles was ≈50 nm, which is smaller than those prepared by the CO 2 laser method. Pre-heating of the carbon rod up to 1000 °C, conducted just before ignition of arc, improved the quality of SWNHs. Transmission electron microscopy, scanning electron microscopy and Raman spectroscopy were used to characterize these SWNH particles.

Carbon nanotubes is synthesized by thermal chemical vapor deposition using acetylene as hydrocarbon gas on Ni-coated silicon substrate. The ‘worm-like’ carbon fibers and ‘spaghetti-like’ carbon nanotubes is grown at 700 °C with the Ni catalyst treated by thermal annealing and H 2 plasma, respectively. It is found that the H 2 plasma treatment is a crucial step to maintain the activity of catalyst prior to the reaction of acetylene gas for the nanotube growth. After clarifying this phenomenon, the carbon nanofibers can successfully be grown at low temperature (500 °C). The field emission test shows both the carbon nanotubes and carbon nanofibers have low turn-on voltage and high emission current, which is sufficient for practical application in the carbon nanotube-/nanofiber-based field emission displays.

A method of synthesizing bulk amounts of single-walled carbon nanohorns (SWNHs) on a significant low-cost basis is proposed based on the 'arc in water' method with N2 injection into the arc plasma. It is elucidated that rapid quenching of the carbon vapour in an inert gas environment is necessary to form the delicate SWNH structures. To realize this reaction field, the arc plasma between the graphite electrodes was isolated from the surrounding water by a thin graphite wall with an N2 flow that excluded reactive gas species (H2O, CO and H2) from the arc zone. High concentrations of SWNHs were found as fine powders floating on the water surface. The particle size distribution of the SWNHs produced by this method was evaluated by dynamic light scattering, resulting in an approximately 70 nm peak diameter.

Carbon nanofilaments were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The structures of carbon nanofilaments were identified as carbon nanotubes or carbon nanofibers. The formation of bamboo-like carbon nanotubes was initiated by the application of the bias voltage during the plasma reaction. The growth kinetics of bamboo-like carbon nanotubes increased with increasing the bias voltage. The growth direction of bamboo-like carbon nanotubes was vertical to the substrate.

A novel method of purification for single-walled carbon nanotubes, prepared by an arc-discharge method, is described. The method involves a combination of acid washing followed by high temperature hydrogen treatment to remove the metal nanoparticles and amorphous carbon present in the as-synthesized single-walled carbon nanotubes. The purified single-walled carbon nanotubes have been characterised by low-angle X-ray diffraction, electron microscopy, thermo-gravimetric analysis and Raman spectroscopy.

Open single-wall carbon nanohorns (SWNHs) were compressed repeatedly at 50 MPa to generate a nanocarbon material of high bulk density. TEM observations and Raman spectroscopy revealed a significant distortion in the structure of the compressed SWNHs. The obtained nanostructured disordered carbon exhibits a high methane storage capacity, reaching 160 cm3/cm3 of nanocarbon at 3.5 MPa and 303 K. Comparison of the experimental results with grand canonical Monte Carlo simulations indicates the importance of the adsorption in the interstitial channels for the high total adsorption capacity of the generated nanostructured carbon.

A modified high-temperature arc furnace was used to produce carbon nanotubes from carbon black by a solid-state transformation without a catalyst. The layer of carbon nanotubes thus formed was nearly pure with only a minor amount of carbon black particles. The properties of these nanotubes were found to be very similar to those produced by the conventional arc synthesis. Based on this process, a mechanism for the growth of these nanotubes is proposed. In addition, field-emission properties of these nanotubes were comparable to the properties of arc-grown carbon nanotubes.

Carbon nanotubes were synthesized via a single-source precursor route at 500 °C, using iron carbonyl both as carbon source and catalyst. The X-ray power diffraction pattern indicates that the products are hexagonal graphite. Transmission electron microscope (TEM) images of the sample reveal carbon nanotubes with an average inner (outer) diameter of 30 nm (60 nm). High-resolution TEM indicates that fabrication of the carbon nanotube walls was composed of ca. 40 graphene layers. The Raman spectrum shows two strong peaks at 1587 and 1346 cm−1, corresponding to the typical Raman peaks of graphitized carbon nanotubes. This method avoids the separation of raw material from solvent and simplifies the operation process. At the same time, the research provides a new route to large-scale synthesis of carbon nanotubes.

Straight carbon nanotubes, carbon nanotube ‘knees’, Y-branches of carbon nanotubes, and coiled carbon nanotubes were grown on a graphite substrate by the decomposition of fullerene under moderate heating (450 °C) in the presence of transition metal particles. The grown structures were investigated without any further manipulation by STM. The observed coiled carbon nanotubes are tentatively identified with the theoretically predicted haeckelite.

Carbon nanostructures synthesized with nanocrystalline Ni catalyst from decomposition of methane are investigated by means of transmission electron microscopy (TEM). Two kinds of carbon nanostructures, carbon fibers and bamboo-shaped carbon nanotubes, are observed. The preferential growth direction of graphene sheets depends on the reaction conditions. The bamboo-shaped carbon nanotubes can be obtained only if the reaction temperature is higher than 1000 K, and carbon fibers can be obtained at lower temperatures. The role and state of the catalyst particles are also discussed.

Recent advances in dye-sensitized solar cells (DSSC), including the use of nanocarbons, resulted in breakthroughs relevant to both the academic and industrial sectors. Their relevance encompasses, on one hand, the development and integration of novel nanocarbon/dye hybrids for superior light-harvesting and improved charge injection properties and, on the other hand, the integration of nanocarbons into each part of DSSCs for enhancing the charge collection efficiency as well as the dye and electrolyte regeneration processes. In the context of the earlier, control over the electron injection and recombination rates is realized on the molecular level. In the context of the latter, i) the charge transport and charge collection efficiencies in the photoelectrode are increased, ii) the charge recombination processes are reduced, when used as a nanocarbon-based buffer layer, iii) the ion diffusion and catalytic effects into (quasi) solid-state electrolytes are improved, and iv) devices using Pt-free counter electrodes with similar device efficiencies are realized. Leading examples of nanocarbons are graphene, carbon black, multi-walled carbon nanotubes, and single-walled carbon nanotubes. In this review, the focus is on a novel carbon allotrope, namely single-walled carbon nanohorns (SWCNH), which is discussed in depth and in comparison with other nanocarbons.

The biomedical applications of carbon nanomaterials, especially integrating noninvasive photothermal therapy (PTT) and photodynamic therapy (PDT), into a single system have enormous potential in cancer therapy. Herein, we present a novel and facile one-step method for the preparation of water-soluble single-walled carbon nanohorns (SWNHs) and metal phthalocyanines (MPc) hybrid for PTT and PDT. The hydrophilic MPc, tetrasulfonic acid tetrasodium salt copper phthalocyanine (TSCuPc), is coated on the surface of SWNHs via noncovalent π-π interaction using the sonication method. In this PTT/PDT nanosystem, SWNHs acts as a photosensitizer carrier and PTT agent, while TSCuPc acts as a hydrophilic and PDT agent. The EPR results demonstrated that the generated reactive oxygen species (ROS) not only from the photoinduced electron transfer process from TSCuPc to SWNHs but also from SWNHs without exciting TSCuPc to its excited state. The test of photothermal conversion proved that not only do SWNHs contribute to the photothermal therapy (PTT) effect, TSCuPc probably also contributes to that when it coats on the surface of SWNHs upon exposure to a 650-nm laser. More importantly, the results of in vitro cell viability revealed a significantly enhanced anticancer efficacy of combined noninvasive PTT/PDT, indicating that the SWNHs-TSCuPc nanohybrid is a hopeful candidate material for developing an efficient and biocompatible nanoplatform for biomedical application.

© 2014 John Wiley & Sons, Inc. Substantial progress and breakthroughs have been achieved for nanomaterials because of their nanometer size. Carbon nanotubes (CNTs), a type of nanomaterial, have received considerable interest worldwide because of their application in clean water technologies. CNTs are seamless cylinder-shaped macromolecules with radii in the nanometer range and lengths of up to several micrometers. Given the modifiable surface properties of CNTs, they are favorable for various applications related to improving and producing clean water technologies. Therefore, the contribution of CNTs in producing clean water is critically assessed in this chapter. A brief introduction to CNTs is presented, and modifications of CNTs to improve their intrinsic properties are discussed. We subsequently discuss the potential application of CNTs in the form of particles and membranes in various water treatment applications. A lifecycle assessment of CNTs in association with their environmental impact is discussed at the end of this chapter.

Jinqian Zhang,1,* Qiang Sun,2,* Jian Bo,3 Rui Huang,4 Mengran Zhang,1 Zhenglin Xia,4 Lili Ju,5 Guoan Xiang4 1Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China; 2Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, People's Republic of China; 3Department of Hematology, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China; 4Department of General Surgery, The Second People's Hospital of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China; 5Department of Neurobiology, Beijing Institute for Brain Disorders, Beijing Center of Neural Regeneration and Repair, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Capital Medical University, Beijing, People's Republic of China *These authors contributed equally to this work Abstract: Single-walled carbon nanohorns (SWNHs) may be useful as carriers for anticancer drugs due to their particular structure. However, the interactions between the material itself and cancerous or normal cells have seldom been studied. To address this problem, the effects of raw SWNH material on the biological functions of human liver cell lines were studied. Our results showed that unmodified SWNHs inhibited mitotic entry, growth, and proliferation of human liver cell lines and promoted their apoptosis, especially in hepatoma cell lines. Individual spherical SWNH particles were found inside the nuclei of human hepatoma HepG2 cells and the lysosomes of normal human liver L02 cells, implying that SWNH particles could penetrate into human liver cells and the different interacted mechanisms on human normal cell lines compared to hepatoma cell lines. Further research on the mechanisms and application in treatment of hepatocellular carcinoma with SWNHs is needed. Keywords: single-walled carbon nanohorns, SWNHs, cell proliferation, cell apoptosis, hepatocellular carcinoma, nucleus, lysosome

The electronic absorption spectrum of single-walled carbon nanohorn (SWCNH) shows a relatively broad absorption peak at 256-259 nm when suspended in tetradecane and in decalin. The electronic absorption spectrum is also characterized by a series of small bands recalling the spectra of C-60 and C-70 fullerenes. Surprisingly, SWCNH shows a minimal solubility in 1,2,4-trichlorobenzene. SWCNH is also dissolved and oxidized in oleum (fuming sulphuric acid with 20% free SO3), displaying a radical cation band in the near infrared at 1045 nm. The addition of ozone to a suspension of SWCNH in oleum enhances its dissolution and the relative radical cation absorption band.

International audience; After a brief reminder of the basics of carbon nanotubes regarding their morphology, structure, texture, and nanotexture, this chapter attempts to summarize the knowledge gathered on every aspect of their properties as the result of the extensive investigation carried out in this field since the 1990s. The properties covered include electrical, thermal, optical, electronic, and adsorptive (chemical reactivity) completed by a summary of the behavior of carbon nanotubes in biological environment, both from the point of view of eco- and cytotoxicity and that of positive (e.g., therapeutic) interactions. An abundant literature is cited for enabling the reader to deepen any selected topic among those addressed here.

Single walled carbon nanohorns (SWCNHs) are a black nanoscale spherical aggregate of cylindrical tubes of graphitic carbon which differ from nanotubes in their "horn-like" shape. Their peculiar structure makes them one of the best electronconductors at a nanoscale level. Although not commercially exploited, their rapid environmental diffusion is expected to rise significantly in the next few years. Therefore, we appraised the ecotoxicology of SWCNH powders by taking into account the ecological role of the two species that were deployed in exposure experiments: polychaetes, Hediste diversicolor, and mussels, Mytilus galloprovincialis. Adult mussels and polychaetes were exposed to three SWCNH concentrations: 1, 5, and 10 mg L-1 and acute effects were measured after 24 and 48 h. Sub-lethal effects were estimated at level of physiological functions such as digestion in mussels (i.e. variations in lysosomal parameters and lipofuscin content) and the antioxidant system in both species (i.e. glutathione peroxidase activity and malondialdehyde content). SWCNH suspension in sea water was also characterised, highlighting the formation of aggregates the size of which was related to SWCNH concentrations and their resident time in the medium. The results showed that SWCNH affected the oxidative and lysosomal systems on the hepatopancreas and led to lysosomal alterations on haemocytes in mussels. The biological responses were less clear in polychaetes. This preliminary investigation highlighted the need of focusing future research efforts on possible physiological impairments caused by long-term exposure to SWCNHs in marine species. (C) 2013 Elsevier B.V. All rights reserved.

Single-walled carbon nanohorns (SWNHs) have great potential to enhance thermal and chemotherapeutic drug efficiencies for cancer therapies. Despite their diverse capabilities, minimal research has been conducted so far to study nanoparticle intracellular transport, which is an important step in designing efficient therapies. SWNHs, like many other carbon nanomaterials, do not have inherent fluorescence properties making intracellular transport information difficult to obtain. The goals of this project were to (1) develop a simple reaction scheme to decorate the exohedral surface of SWNHs with fluorescent quantum dots (QDs) and improve conjugate stability, and (2) evaluate SWNH–QD conjugate cellular uptake kinetics and localization in various cancer cell lines of differing origins and morphologies. In this study, SWNHs were conjugated to CdSe/ZnS core/shell QDs using a unique approach to carbodiimide chemistry. Transmission electron microscopy and electron dispersive spectroscopy verified the conjugation of SWNHs and QDs. Cellular uptake kinetics and efficiency were characterized in three malignant cell lines: U-87 MG (glioblastoma), MDA-MB-231 (breast cancer), and AY-27 (bladder transitional cell carcinoma) using flow cytometry. Cellular distribution was verified by confocal microscopy, and cytotoxicity was also evaluated using an alamarBlue assay. Results indicate that cellular uptake kinetics and efficiency are highly dependent on cell type, highlighting the significance of studying nanoparticle transport at the cellular level. Nanoparticle intracellular transport investigations may provide information to optimize treatment parameters (e.g., SWNH concentration, treatment time, etc.) depending on tumor etiology.

Single-wall carbon nanohorn aggregates were characterized by N2 adsorption at 77 K and `particle density' measurement using the high pressure He buoyancy method. The single-wall carbon nanohorn aggregate had micropores and its pore volume was 0.11 ml g −1 . The particle density was 1.25 g ml −1 . The particle density was not equal to the solid density of graphite (2.27 g ml −1 ) , but it agreed within 15% with the density of the single-wall carbon nanohorn estimated using previous TEM data. Hence single-wall carbon nanohorns have closed micropores covered with single graphene walls. According to N2 adsorption, single-wall carbon nanohorns have a considerably large surface area (308 m 2 g −1 ) and open microporosity which has been ascribed to the inter-particle aggregate structure, the so-called `dahlia flower type structure'.

Chemical doping of single-wall carbon nanohorns (SWNHs) with K and Br was examined by vapor-phase reaction and studied by Raman scattering. Electro-chemical Li-ion doping using an electrolyte of LiAsF6 in a mixture (1:1 by volume) of ethylene carbonate and diethyl carbonate was also carried out. All these experiments indicate that an anomalously small charge transfer occurs in saturation-doped SWNHs using these reagents, in sharp contrast to the behavior observed for single-wall carbon nanotube bundles and graphite. This rather remarkable result is not understood at present.

The recently discovered single-wall carbon nanohorns (SWNH) are found to adsorb liquid ethanol effectively. The amount of liquid ethanol adsorbed by SWNHs is about 3.5 times larger than that of a super high surface area carbon. It is also found that SWNHs act as a catalyst for the oxidation of ethanol into acetaldehyde. Their thermal stability in oxygen is also discussed.

K-doping into the aggregate of single-wall carbon nanohorns (SWNHs) and into the bundle of single-wall carbon nanotubes (SWNTs) are introduced in this study. Electron spin resonance (ESR) of the pristine SWNHs and SWNTs show that the pristine SWNHs are ESR active and the linewidth (ΔH) is susceptive to the partial pressure of O2, while the pristine SWNTs are ESR silent. ΔH of K-doped SWNHs becomes wider by a factor of −2 than that of the pristine one. For K-doped SWNTs, the Dysonian type ESR comes to be observed. Details of the ESR features are discussed.

We have found a new type of carbon particle produced by the CO 2 laser ablation of carbon at room temperature without a metal catalyst. The product has a powder form of graphitic particles with a uniform size of about 80 nm. An individual particle is composed of an aggregate of many horn-shaped sheaths of single-walled graphene sheets, which we named carbon nano-horns. The nano-horns can be produced at about 10 g/h.

1169 Carbon nanotubes, long, thin cylinders of carbon, about 10.000 times thinner than a human hair, were discovered in 1991 by Sumio Iijima. These are large macromolecules that are unique for their size, shape, and remarkable physical properties. From chemical point of view, the carbon nanotubes consist of SP 2 bonded carbon atoms, the same as found in graphite. The structure of graphite is very strong in one plane due to the covalent bonding between the carbon atoms, but is weak between planes because there is no covalent bonding, only Van der Waals forces acting. The electrical conductance determination of single-wall and double-wall carbon nanotube systems was a central task, theoretical and experimental, of the scientific research at nanometer scale on advanced materials, in the past five years. Due to the importance of the chosen structure configuration in solving this difficult problem, further on we shall present few general notions on the reactivity and the structure of nanotubes. Reactivity of the fullerene molecules with respect to addition chemistries is strongly dependent on the curvature of the carbon framework. Their outer surface (exohedral) reactivity increases with increase in curvature. In comparison with fullerene molecules Single-Walled Carbon Nanotubes (SWCN’s) are moderately curved. Consecutively, nanotubes are expected to be less reactive than most fullerene molecules due to their smaller curvature, but more reactive than a graphene sheet due to pyramidalization and misalignment of pi

The large diameter of single-wall carbon nanohorns (SWNHs) allows various molecules to be easily incorporated in hollow nanospaces. In this report, we prove that the nanospaces of SWNHs even work as the chemical reaction field at high temperature; that is, Gd-acetate clusters inside SWNHs were transformed into ultrafine Gd(2)O(3) nanoparticles with their particle size retained even after heat-treatment at 700 degrees C. This indicates that the confinement of the Gd-acetate clusters in a deep potential well of the SWNH nanospaces prevented a migration to form larger particles, giving rise to ultrafine Gd(2)O(3) nanoparticles of 2.3 nm in average diameter, which is much smaller than the case without SWNHs. The Gd(2)O(3) nanoparticles thus obtained were demonstrated to be actually useful to the magnetic resonance imaging. We believe that the presented effectiveness of the inner hollow spaces of SWNHs, therefore, also those of the carbon nanotubes, for high-temperature chemical reactions should be highlighted, and that the thus produced novel nanomaterials are promising to expand the fields of nanoscience.

Fine and long multiwalled carbon nanotubes attached with less carbon nanoparticles were prepared by d.c. arc discharge plasma of graphite electrodes in hydrogen gas. These high-grade carbon nanotubes grew on the central part of the cathode as a carbon deposit like black soot. They were mainly observed by a scanning electron microscope and subsequently by a high resolution transmission electron microscope. By comparing with helium and methane gases, the predominance of the use of hydrogen gas as the environmental gas is discussed. A new type of carbon allotrope, namely petal-like graphite sheets consisting of a number of interlaced graphene sheets, was also found in the outside region surrounding the central cathode deposit.

A novel sandwich-type electrochemical immunosensor based on functionalized nanomaterial labels and bienzyme (horseradish peroxidase and glucose oxidase) biocatalyzed precipitation was developed for the detection of α-fetoprotein (AFP). The enzymes linked to functionalized nanomaterials as biocatalysts could accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to yield the insoluble product on the electrode surface; the mass loading of the precipitates on the device led to a significant enhanced signal. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to monitor the enhanced precipitation of 4-CN that accumulated on the electrode surface and subsequent decrement in the electrode surface area by monitoring the reduction process of the Fe(CN)6(4-/3-) redox couple. Under optimal conditions, the proposed immunosensor showed a high sensitivity and a wide linear range from 0.001 to 60 ng mL(-1) with a low detection limit of 0.33 pg mL(-1). Moreover, the immunosensor exhibited good selectivity, acceptable stability and reproducibility. The amplification strategy showed good promise for clinical screening of tumor biomarkers.

A critical limiting factor of chemotherapy is the unacceptably high toxicity. The use of nanoparticle based drug carriers has significantly reduced the side effects and facilitated the delivery of drugs. Source of the remaining side effect includes (1) the broad final in vivo distribution of the administrated nanoparticles, and (2) strong basal drug release from nanoparticles before they could reach the tumor. Despite the advances in pH-triggered release, undesirable basal drug release has been a constant challenge under in vivo conditions. In this study, functionalized single walled carbon nanohorn supported immunoliposomes were assembled for paclitaxel delivery. The immunoliposomes were formulated with polyethylene glycol, thermal stable and pH sensitive phospholipids. Each nanohorn was found to be encapsulated within one immunoliposome. Results showed a highly pH dependent release of paclitaxel in the presence of serum at body temperature with minimal basal release under physiological conditions. Upon acidification, paclitaxel was released at a steady rate over 30 days with a cumulative release of 90% of the loaded drug. The drug release results proved our hypothesized double controlled release mechanism from the nanoparticles. Other results showed the nanoparticles have doubled loading capacity compared to that of traditional liposomes and higher affinity to breast cancer cells overexpressing Her2 receptors. Internalized nanoparticles were found in lysosomes. Published version

Using realistic models of single-walled carbon nanohorns and their single-walled carbon nanotube counterparts, we study the equilibrium separation of CO2–CH4 mixtures near ambient operating conditions by using molecular simulations. We show that regardless of the studied operating conditions (i.e., total CO2–CH4 mixture pressures and mole fractions of mixture components in the bulk phase), single-walled carbon nanohorns maximize the CO2–CH4 equilibrium separation factor. Optimized samples of single-walled carbon nanohorns consisting of narrow tubular parts capped with horn-shaped tips show highly selective adsorption of CO2 over the CH4 mixture component, with the CO2–CH4 equilibrium separation factor of ∼8–12. A large surface-to-volume ratio (i.e., enhanced surface forces) and unique defective morphology (i.e., packing of adsorbed molecules in quasi-one/quasi-zero dimensional nanospaces) of single-walled carbon nanohorns are their key structural properties responsible for the excellent separation performance. Our theoretical simulation results are in quantitative agreement with a recent experimental/theoretical study of the CO2–CH4 adsorption and separation on oxidized single-walled carbon nanohorns [Ohba et al., Chem. Lett., 40, 2011, 1089]. Both experiment and theory showed that the CO2–CH4 equilibrium separation factor of oxidized samples of single-walled nanohorns measured near ambient operating conditions is ∼2–5. This reduction in the separation efficiency as compared to optimized samples of single-walled carbon nanohorns is theoretically justified by their lower surface-to-volume ratio (i.e., larger diameters of tubular parts and horn-shaped tips).

A new image analysis method called the spatial phantom evaluation of cellular thermal response in layers (SPECTRL) is presented for assessing spatial viability response to nanoparticle enhanced photothermal therapy in tissue representative phantoms. Sodium alginate phantoms seeded with MDA-MB-231 breast cancer cells and single-walled nanohorns were laser irradiated with an ytterbium fiber laser at a wavelength of 1064 nm and irradiance of 3.8 W cm(-2) for 10-80 s. SPECTRL quantitatively assessed and correlated 3D viability with spatiotemporal temperature. Based on this analysis, kill and transition zones increased from 3.7 mm(3) and 13 mm(3) respectively to 44.5 mm(3) and 44.3 mm(3) as duration was increased from 10 to 80 s. SPECTRL provides a quantitative tool for measuring precise spatial treatment regions, providing information necessary to tailor therapy protocols.

Single-wall carbon nanohorns (SWNHs) have been demonstrated to accumulate in cytotoxic levels within organs of various animal models and cell types, which emerge as a wide range of promising biomedical imaging. Septic encephalopathy (SE) is an early sign of sepsis and associated with an increased rate of morbidity and mortality. Microglia activation plays an important role in neuroinflammation, which contributes to neuronal damage. Inhibition of microglia activation may have therapeutic benefits, which can alleviate the progression of neurodegeneration. Therefore, we investigated the functional changes of mice microglia cell lines pre-treated with or without lipopolysaccharide (LPS) induced by SWNHs. To address this question, the research about direct role of SWNHs on the growth, proliferation, and apoptosis of microglia cell lines in mice (N9 and BV2) pre-treated with or without LPS had been performed. Our results indicate that the particle diameter of SWNHs in water is between 342 to 712 nm. The images in scanning electron microscope showed that SWNHs on polystyrene surface are individual particles. LPS induced activation of mice microglia, promoted its growth and proliferation, and inhibited its apoptosis. SWNHs inhibited proliferation, delayed mitotic entry, and promoted apoptosis of mice microglia cells. The effects followed gradually increasing cultured time and concentrations of SWNHs, especially in cells pre-treated with LPS. SWNHs induced a significantly increase in G1 phase and inhibition of S phase of mice microglia cells in a dose-manner dependent of SWNHs, especially in cells pre-treated with LPS. The transmission electron microscope images showed that individual spherical SWNH particles smaller than 100 nm in diameters were localized inside lysosomes of mice microglia cells. SWNHs inhibited mitotic entry, growth and proliferation of mice microglia cells, and promoted its apoptosis, especially in cells pre-treated with LPS. SWNHs inhibited expression of Sirt3 and energy metabolism related with Sirt3 in mice microglia cells in a dose-dependent manner, especially in cells pre-treated with LPS. The role of SWNHs on mice microglia was implicating Sirt3 and energy metabolism associated with it.

Multi-walled carbon nanotubes (MWCNTs) are elongated cylindrical nanoobjects made of sp2 carbon. Their diameter is 3–30 nm and they can grow several cm long, thus their aspect ratio can vary between 10 and ten million. They can be distinguished from single-walled carbon nanotubes on the basis of their multi-walled Russian-doll structure and rigidity, and from carbon nanofibers on the basis of their different wall structure, smaller outer diameter, and hollow interior. This chapter introduces MWCNT synthesis methods, discusses the chemistry and properties of multi-walled carbon nanotubes, and gives examples of their application. References to single-walled carbon nanotubes (SWNT) are kept at a minimum.

The synthesis of well-aggregated carbon nanotubes in the form of bundles was achieved by the catalytic reduction of 1,2-dichlorobenzene by a solvothermal approach. The use of 1,2-dichlorobenzene as a carbon source yielded a comparably good percentage of carbon nanotubes in the range of 60–70 %, at a low reaction temperature of 200°C. The products obtained were analysed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The X-ray diffraction studies implied the presence of pure, crystalline, and well-ordered carbon nanotubes. The scanning electron and transmission electron microscopic images revealed the surface morphology, dimensions and the bundled form of the tubes. These micrographs showed the presence of multi-walled carbon nanotubes with an outer diameter of 30–55 nm, inner diameter of 15–30 nm, and lengths of several hundreds of nanometers. Brunauer-Emmett-Teller-based N2 gas adsorption studies were performed to determine the surface area and pore volume of the carbon nanotubes. These carbon nanotubes exhibit a better surface area of 385.30 m2 g−1. In addition, the effects of heating temperature, heating time, amount of catalyst and amount of carbon source on the product yield were investigated.

Single-walled carbon nanotubes (SWCNTs) are hollow, long cylinders with extremely large aspect ratios, made of one atomic sheet of carbon atoms in a honeycomb lattice. They possess extraordinary thermal, mechanical, and electrical properties and are considered as one of the most promising nanomaterials for applications and basic research. This chapter describes the structural, electronic, vibrational, optical, transport, mechanical, and thermal properties of these unusual one-dimensional (1-D) nanomaterials. The crystallographic (Sect. 4.2.1), electronic (Sect. 4.2.2), vibrational (Sect. 4.2.3), optical (Sect. 4.4), transport (Sect. 4.5), thermal (Sect. 4.6.1), and mechanical (Sect. 4.6.2) properties of these unusual 1-D nanomaterials will be outlined. In addition, we will provide an overview of the various methods developed for synthesizing SWCNTs in Sect. 4.3.

A method for the thiolation of single-wall carbon nanotubes has been developed by exposing a sulfur/carbon nanotubes mixture to an argon/hydrogen gaseous plasma. X-ray photoelectron spectroscopy provides evidence of the existence of sulfur attached to carbon on the carbon nanotubes samples and Raman spectroscopy results show that the carbon nanotubes’ structure has been preserved after the treatment. One added advantage of the reported method is that excess oxygen is not present on the nanotubes. The thiolated carbon nanotubes are shown to self-assemble onto gold electrodes. Our method for thiolating carbon nanotubes provides a reliable and simple way for preparing functionalized tubes for nanoelectronic circuits based on carbon nanotubes.

A new modelling-aided approach for the atomistic model of single walled carbon nanohorn (SWNH) creation is presented, based on experimental evidence, on realistic potential of carbon-carbon interactions and on molecular simulations. A new model of SWNHs is next used to predict Ar adsorption properties and to check the molecular fundamentals of the adsorption mechanism. The influence of the apex angle value, nanohorn diameter and nanohorn length on the shapes of isotherms, enthalpy, high resolution α(s)-plots and adsorption potential distribution curves is checked. Finally the comparison with new experimental Ar adsorption results is shown and the conclusions on the porosity of real SWNH aggregates are given.

Laser-based photothermal therapies for urothelial cell carcinoma (UCC) are limited to thermal ablation of superficial tumors, as treatment of invasive lesions is hampered by shallow light penetration in bladder tissue at commonly used therapeutic wavelengths. This study evaluates the utilization of sharp, silica, fiberoptic microneedle devices (FMDs) to deliver single-walled carbon nanohorns (SWNHs) serving as exogenous chromophores in conjunction with a 1064 nm laser to amplify thermal treatment doses in a spatially controlled manner. Experiments were conducted to determine the lateral and depth dispersal of SWNHs in aqueous solution (0.05 mg/mL) infused through FMDs into the wall of healthy, inflated, ex vivo porcine bladders. SWNH perfused bladder regions were irradiated with a free-space, CW, 1064 nm laser in order to determine the SWNH efficacy as exogenous chromophores within the organ. SWNHs infused at a rate of 50 μL/min resulted in an average lateral expansion rate of 0.36 ± 0.08 cm(2)/min. Infused SWNHs dispersal depth was limited to the urothelium and muscular propria for 50 μL/min infusions of 10 minutes or less, but dispersed through the entire thickness after a 15 minute infusion period. Irradiation of SWNH perfused bladder tissue with 1064 nm laser light at 0.95 W/cm(2) over 40 seconds exhibited a maximum increase of approximately 19°C compared with an increase of approximately 3°C in a non-perfused control. The results indicate that these silica FMDs can successfully penetrate into the bladder wall to rapidly distribute SWNHs with some degree of lateral and depth control and that SWNHs may be a viable exogenous chromophore for photothermal amplification of laser-based UCC treatments.

A surface-assisted laser desorption/ionization time-of-flight mass spectrometric (SALDI-TOF MS) method was developed for the analysis of small biomolecules by using functional single-walled carbon nanohorns (SWNHs) as matrix. The functional SWNHs could transfer energy to the analyte under laser irradiation for accelerating its desorption and ionization, which led to low matrix effect, avoided fragmentation of the analyte, and provided high salt tolerance. Biomolecules including amino acids, peptides, and fatty acids could successfully be analyzed with about 3- and 5-fold higher signals than those obtained using conventional matrix. By integrating the advantages of SWNHs and the recognition ability of aptamers, a selective approach was proposed for simultaneous capture, enrichment, ionization, and MS detection of adenosine triphosphate (ATP). This method showed a greatly improved detection limit (1.0 μM) for the analysis of ATP in complex biological samples. This newly designed protocol not only opened a new application of SWNHs, but also offered a new technique for selective MS analysis of biomolecules based on aptamer recognition systems.

Cancer is one of the most deadly diseases and leading cause of death. Laser based photothermal therapy can provide a minimally invasive alternative to surgical resection. The selectivity and effectiveness of laser therapy can be greatly enhanced when photoabsorbing nanoparticles such as nanoshells, single walled carbon nanotubes, multi-walled carbon nanotubes, or single wall carbon nanohorns (SWNHs) are introduced into the tissue[1]. Quantitative methods for measuring tumor response to nanoparticle enhanced laser therapies are critical for determining appropriate laser parameters and nanoparticle properties needed to achieve maximum therapeutic benefit. We have previously reported a new method for measuring two dimensional (2D) spatial viability distributions in cell monolayers in response to laser irradiation and nanoparticles. This method has been refined to allow determination of cell viability in three dimensions (3D) within a more physiologically representative tumor volume. This refined method was used to determine the viability of breast cancer cells suspended within sodium alginate tissue phantoms following treatment with SWNHs and external laser irradiation. The tumor treatment volume was accurately quantified in response to varying laser treatment parameters and nanoparticle concentrations. Spatial cellular viability was also measured in ex vivo pig bladders in response to SWNHs and laser irradiation to provide a more anatomically relevant environment. These new measurement methods enable quantification of spatial viability and therapeutic effectiveness, using 3D tumor environments which are more representative than cell monolayers.Copyright © 2012 by ASME

Laser based photothermal therapy is a minimally invasive technique that relies on the absorption of energy by an irradiated tissue sample and results in the deposition of heat to destroy cancerous cells. The inclusion of nanoparticles that act as intense infrared absorbers allows for higher selectivity and additional absorption of laser energy into heat in the desired material. One promising carbonaceous nanoparticle is single walled carbon nanohorns (SWNHs) which have been demonstrated to be effective photoabsorbers [1].Copyright © 2012 by ASME

Proteases play a central role in several widespread diseases. Thus, there is a great need for the fast and sensitive detection of various proteolytic enzymes. Herein, we have developed a carbon nanotube (CNT)-based protease biosensing platform that uses peptides as a fluorescence probe for the first time. Single-walled carbon nanohorns (SWCNHs) and thrombin were used to demonstrate this detection strategy. SWCNHs can adsorb a fluorescein-based dye (FAM)-labeled peptide (FAM-pep) and quench the fluorescence of FAM. In contrast, thrombin can cleave FAM-pep on SWCNHs and recover the fluorescence of FAM, which allows the sensitive detection of thrombin. This biosensor has a high sensitivity and selectivity toward thrombin, with a detection limit of 100 pM.