Showing papers by "Malcolm L. H. Green published in 2010"
TL;DR: Covalent functionalization of radionuclide-filled single-walled carbon nanotubes and their use as radioprobes is reported and it is envisaged that organ-specific therapeutics and diagnostics can be developed on the basis of the nanocapsule model described here.
Abstract: Functionalization of nanomaterials for precise biomedical function is an emerging trend in nanotechnology. Carbon nanotubes are attractive as multifunctional carrier systems because payload can be encapsulated in internal space whilst outer surfaces can be chemically modified. Yet, despite potential as drug delivery systems and radiotracers, such filled-and-functionalized carbon nanotubes have not been previously investigated in vivo. Here we report covalent functionalization of radionuclide-filled single-walled carbon nanotubes and their use as radioprobes. Metal halides, including Na(125)I, were sealed inside single-walled carbon nanotubes to create high-density radioemitting crystals and then surfaces of these filled-sealed nanotubes were covalently modified with biantennary carbohydrates, improving dispersibility and biocompatibility. Intravenous administration of Na(125)I-filled glyco-single-walled carbon nanotubes in mice was tracked in vivo using single-photon emission computed tomography. Specific tissue accumulation (here lung) coupled with high in vivo stability prevented leakage of radionuclide to high-affinity organs (thyroid/stomach) or excretion, and resulted in ultrasensitive imaging and delivery of unprecedented radiodose density. Nanoencapsulation of iodide within single-walled carbon nanotubes enabled its biodistribution to be completely redirected from tissue with innate affinity (thyroid) to lung. Surface functionalization of (125)I-filled single-walled carbon nanotubes offers versatility towards modulation of biodistribution of these radioemitting crystals in a manner determined by the capsule that delivers them. We envisage that organ-specific therapeutics and diagnostics can be developed on the basis of the nanocapsule model described here.
260 citations
TL;DR: In this article, the effects of a good dispersion of as much as 10.5% multiwalled carbon nanotubes (MWCNTs) on the mechanical properties of dense alumino-borosilicate glass ceramics (ABS) were investigated.
94 citations
TL;DR: Graphene nanoflakes (GNFs) with average diameters of ∼30 nm have been prepared by a single-step oxidation procedure using single-wall carbon nanotube arc-discharge material and nitric acid as discussed by the authors.
Abstract: Graphene nanoflakes (GNFs) with average diameters of ∼30 nm have been prepared by a single-step oxidation procedure using single-wall carbon nanotube arc-discharge material and nitric acid. The GNFs are predominately single sheets containing a small number of internal defects. The edges are decorated with primarily carboxylic acid groups which allow facile chemical functionalisation and cross-linking of the fragments using multivalent cations.
46 citations
TL;DR: Dimethylamino-functionalized fullerenes (pf-C60) have been used as removable "corks" at the openings of filled single-walled carbon nanotubes (SWCNTs).
39 citations
TL;DR: In this paper, a bifurcated hydrogen bond between the tetrafluoroborate anions and the central imidazolinium proton (NCHN−) was found.
32 citations
TL;DR: In this article, the ferromagnetic properties of carbon nanotubes were investigated and it was shown that the origin of FM in carbon Nanotubes is mainly from the hydrogen chemisorptions induced in the process of acid purification.
Abstract: The pure double-walled carbon nanotubes (DWNTs) and two endohedral DWNTs (DWNTs with materials filled inside) are produced. The filling materials are CoI2 and KI, respectively. The ferromagnetism (FM) is observed in pure DWNTs. The content of residual catalyst Fe is too small to be responsible for the observed FM. On the other hand, after filling KI or CoI2 into the tubes, over 87% of FM is suppressed. This suggests that the origin of FM in nanotubes is mainly from the hydrogen chemisorptions induced in the process of acid purification. With the knowledge of FM origin, it is then possible to enhance FM of carbon nanotubes or graphene for applications relying on magnetism.
15 citations
TL;DR: In this paper, the presence of caesium iodide inside WS2 nanotubes has been determined using high-resolution transmission electron microscopy (HRTEM) coupled with electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopic (EDS).
Abstract: WS2 nanotubes have been filled and intercalated by molten phase caesium iodide. The presence of caesium iodide inside the WS2 nanotubes has been determined using high-resolution transmission electron microscopy (HRTEM) coupled with electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopy (EDS). Noticeably, a Moire pattern was observed due to the interference between encapsulated CsI and WS2 layers. The intercalation of CsI into the host concentric WS2 lattices resulted in an increase in the interplanar spacing.
13 citations
TL;DR: In this article, a new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core-shell nanotubular structures by using multiwall WS2 nanotubes as host templates.
Abstract: Various inorganic salts can be encapsulated inside the comparatively narrow (0.8-2 nm) hollow core of single-walled carbon nanotubes (SWNTs) by molten phase capillary wetting. A new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core-shell nanotubular structures by using multiwall WS2 nanotubes as host templates. Molten phase wetting with CsI results in the formation of 1D crystal structures inside WS2 nanocapillaries with a Moire pattern. The relatively large diameter of the WS2 nanotube (with inner and outer diameters of ca. 10 and 20 nm, respectively), allows a conformal folding of the guest PbI2 layers (PbI2@WS2 core-shell nanotubes) on the interior wall of the WS2 nanotube-template, thus leading to relatively defect-free core-shell inorganic nanotubular structures, which have not been previously observed within carbon nanotubes (CNTs). Core-shell WS2@MoS2 nanotubes can be obtained by the gas-phase reaction of MoCl5 with sulfur in the presence of WS2 nanotubes. The mechanism of imbibition/solidification of the molten salt into the hollow cores of MoS2 nanotubes has been studied by molecular dynamics simulations, showing major differences between layered compounds and those with quasi-isotropic structure. Theoretical considerations also show the conditions for the stability of such core-shell 1D nanostructures. These new strategies can open up many possibilities for the synthesis of new nanotubular structures.
13 citations
TL;DR: In this paper, the authors proposed to remove the unwanted material external to the SWNT walls by using fullerenes to "cork" open-ended SWNTs and observed that this can be achieved by closing the ends of the SW NTs or by using a fullerene-based closure.
Abstract: Filled carbon nanotubes are of increased interest due to their potential in a wide variety of applications including drug delivery systems, data storage and nano-electronic devices. Bulk filling of carbon nanotubes always results in samples containing a large amount of unwanted material external to the SWNT walls. For the envisaged applications of filled carbon nanotubes it is necessary to remove the external materials whilst preserving the material encapsulated in the SWNTs. We have observed that this can be achieved by closing the ends of the SWNTs or by using fullerenes to “cork” open-ended SWNTs. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
12 citations
TL;DR: In this article, a novel square planar Pd(II) α-diimines [PdX2{ArN C(Cl)}2], where Ar = C6H5, (2,6-Me2C6H3), and X = Cl or Br, have been prepared and characterised by spectroscopic methods.
11 citations
TL;DR: A new and simple strategy for the dispersion of single-wall carbon nanotubes in aqueous media is presented which does not rely on hydrophobic interactions between the polypeptidic dispersing agent and the nanot tubes, and allows the surface charge of the resulting conjugate materials to be controlled.
TL;DR: In this article, a new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core-shell nanotubular structures by using multiwall WS2 nanotubes as host templates.
Abstract: Various inorganic salts can be encapsulated inside the comparatively narrow (0.8-2 nm) hollow core of single-walled carbon nanotubes (SWNTs) by molten phase capillary wetting. A new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core-shell nanotubular structures by using multiwall WS2 nanotubes as host templates. Molten phase wetting with CsI results in the formation of 1D crystal structures inside WS2 nanocapillaries with a Moire pattern. The relatively large diameter of the WS2 nanotube (with inner and outer diameters of ca. 10 and 20 nm, respectively), allows a conformal folding of the guest PbI2 layers (PbI2@WS2 core-shell nanotubes) on the interior wall of the WS2 nanotube-template, thus leading to relatively defect-free core-shell inorganic nanotubular structures, which have not been previously observed within carbon nanotubes (CNTs). Core-shell WS2@MoS2 nanotubes can be obtained by the gas-phase reaction of MoCl5 with sulfur in the presence of WS2 nanotubes. The mechanism of imbibition/solidification of the molten salt into the hollow cores of MoS2 nanotubes has been studied by molecular dynamics simulations, showing major differences between layered compounds and those with quasi-isotropic structure. Theoretical considerations also show the conditions for the stability of such core-shell 1D nanostructures. These new strategies can open up many possibilities for the synthesis of new nanotubular structures.
TL;DR: The use of NiI 2 -filled carbon nanotubes (CNTs) for the synthesis of GaN nanowires (NWs) was demonstrated in this article.
TL;DR: In this paper, two classes of two-electron three-centre bonds are discussed and the manner in which the se two types of bonds differ in their interaction with each other is shown.
Abstract: A brief personal account of the relation of the author with Professor Gordon Stone is described. Then the two parts of the scientific presentation of the symposium talk is given. The first part shows that there are two classes of two-electron three-centre bonds. And the manner in which the se two types of bonds differ in their interaction with each other is shown. For example in the Class II 2e-3c bond the central bridging atom formally contributes two electrons to each of the other two atoms, in terms of electron counting considerations. The second part describes how carbon nanotubes, decorated with sugar molecules on the outside and filled with radioactive iodine, sealed in the interior of the SWNTs can be delivered selectively to the lungs of a mouse. The radio nuclei are selectively located in exceptionally high concentrations and this has implications for applications in radio surgery.