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Quantification of the cellular uptake of nanomaterials is crucial for studies of their toxicity and medical applications. However, our knowledge of the behaviors of carbon nanotubes (CNTs) in cells or tissues remains incomplete due to the lack of appropriate methods for quantitative analysis. Here, we present a unique methodology for quantitatively assessing the cellular uptake of CNTs, taking advantage...
Here, we carried out synthesis of single-walled carbon nanotubes (SWCNTs) in an ultra-high vacuum chamber by alcohol catalytic chemical vapor deposition (ACCVD) using Rh nanoparticles as catalysts. By optimizing the ethanol pressure precisely, we succeeded in growth of good-quality SWCNTs at 270 °C, which is a record of the lowest temperature for the SWCNT growth. The activation energy for SWCNT growth...
Boron- and nitrogen-codoped single walled carbon nanohorns (BN-SWCNHs) were prepared by CO2 laser ablation of a boron-containing carbon target under nitrogen atmosphere. The structures were spherical SWCNH aggregates containing many graphite-like thin sheets (GLSs), which was different from general SWCNHs. X-ray photoelectron spectra indicated that the doped quantities of boron and nitrogen were about...
Adsorption of polyethylene glycol conjugated phospholipids with various PEG chain length (DSPE-PEG5000, 2000, 750) onto single-walled carbon nanohorns (SWCNH), a type of graphene nano-tubule, in aqueous solution was investigated by means of high-resolution magic angle spinning (HRMAS) 1H NMR. Peak integral ratio of PEG chains and alkyl chains of DSPE-PEGs in the NMR spectra linearly decreased to zero...
We study single-walled carbon nanotube (SWCNT) growth from Pt catalysts by a cold-wall chemical vapor deposition (CVD) method in a high vacuum using a nozzle injector for the ethanol gas supply. By optimizing the ethanol pressure, we could grow SWCNTs between 330 and 700 °C, and the optimal ethanol pressure to obtain the highest SWCNT yield was reduced as the growth temperature decreased. Using transmission...
Boron neutron capture therapy requires boron carriers that can deliver abundant boron to tumors. To obtain such a carrier, we have prepared boron nitride (BN) containing carbon nanohorn aggregate (CNH) by heating CNHs with ammonia borane at 800°C. The obtained BN-CNH had a C:B:N mole ratio of 5:2:2, as estimated from X-ray photoemission spectroscopy. The nanohorn tubule walls had graphene–BN double...
Nanopores (pores between 1 and 5nm) have been the object of a great deal of attention because they can selectively adsorb relatively large molecules such as macromolecules and polymer molecules. Conventional methods for analyzing porous structures—such as N 2 adsorption measurements at 77K—can be used to investigate microporous and mesoporous structures, but there is a lack of investigation...
Photothermal conversion of nanocarbons has potential applications in medical and energy engineering. It is expected that the photothermal conversion of tubular nanocarbons can thermally enhance polymer formation on their surfaces and insides. We show in this report that light irradiation enhanced the catalytic polymerization of caprolactone (CL) on tubular carbon nanohorns, and polycaprolactone (PCL)...
Nitrogen-doped single wall carbon nanohorns (N-SWCNHs) were prepared by CO2 laser ablation of a graphite target under nitrogen atmosphere. X-ray photoelectron spectra showed that the doped nitrogen quantities were about 1.7 and 1.1at.% under nitrogen and nitrogen/Ar mixed atmospheres, respectively. The nitrogen atoms were implicated as the pyridine-like and threefold coordinated sp2 bonding in graphene...
Graphite-like thin sheets (GLSs) contained in globular aggregates of carbon nanohorns have few oxygenated groups; therefore, they are suitable for studying how oxidation can be finely controlled. We found that mild oxidation in GLSs with H 2 O 2 solution at room temperature for 7–28days enabled GLS surface layers to be selectively oxidized, where carboxyl, quinone, carbonyl, and hydroxyl...
Carbon nanomaterials, such as single-walled carbon nanohorns (SWCNHs) and carbon nanotubes, demonstrate great potential as drug delivery systems. However, no reports to date have detailed the use of SWCNHs as oral drug carriers. This study shows for the first time the actions of orally-administered SWCNHs in normal mice and mice with dextran sulfate sodium (DSS)-induced colitis. SWCNHs labeled with...
The graphite-like thin sheets (GLSs) used in this study were prepared by laser ablation of graphite in argon gas. The obtained GLSs were neat, untouched and free-standing. We discovered a new phenomenon with them: even layer numbers (2, 4, 6, and 8) preferentially formed, and their population decreased as the layer number increased. This suggests a new growth mechanism in which single-layer GLSs bend...
Roll-to-roll microwave plasma chemical vapor deposition (CVD) has been used for the continuous deposition of graphene films for industrial mass production. Using surface wave plasma, a pair of roll-to-roll winder and unwinder system has been built into a CVD apparatus, which has a deposition area of 294mm×480mm. A graphene film was deposited onto the Cu film with 294mm width under CH 4 /Ar/H...
We succeeded in morphology-selective preparation of single-wall carbon nanohorn (SWCNH) aggregates by changing the buffer gas (760Torr) in CO 2 laser ablation of graphite: He for seed type, N 2 , Ar and Ne for dahlia type, and Kr for petal dahlia type. In Xe, aggregates of thin graphene sheets were the major product. The degree of graphitization increased with the mass number of the...
We created holes in single-wall carbon nanohorns (SWCNH) by oxidation (SWCNHox) and investigated how the hole size affected the incorporation of C 60 in SWCNHox and their release from it. The incorporation of C 60 inside SWCNHox first occurred when the holes were opened by oxidation at 475°C. It was followed by a steep increase in the incorporation quantity with increasing oxidation...
Boron-doping of carbon nanohorn-aggregates was carried out by using arc-vaporization of a boron-containing composite carbon rod in a balanced gas of Ar with 5% of O 2 . Transmission and scanning electron microscopy revealed that the obtained sample powder consisted of high purity nanohorn-aggregates. The temperature dependence of the electrical resistivity of a pellet formed from the sample...
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