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Innocenti A.,University of Florence | Durdagi S.,University of Calgary | Doostdar N.,Richard E Smalley Institute For Nanoscale Science And Technology | Amanda Strom T.,Richard E Smalley Institute For Nanoscale Science And Technology | And 3 more authors.
Bioorganic and Medicinal Chemistry | Year: 2010

We investigated a series of derivatized fullerenes possessing alcohol, amine, and amino acid pendant groups as inhibitors of the zinc enzymes carbonic anhydrases (CAs, EC We discovered that fullerenes bind CAs with submicromolar-low micromolar affinity, despite the fact that these compounds do not possess moieties normally associated with CA inhibitors such as the sulfonamides and their isosteres, or the coumarins. The 13 different mammalian CA isoforms showed a diverse inhibition profile with these compounds. By means of computational methods we assessed the inhibition mechanism as being due to occlusion of the active site entrance by means of the fullerene cage (possessing dimension of the same order of magnitude as the opening of the enzyme cavity, of 1 nm). The pendant moieties to the fullerene cage make interactions with amino acid residues from the active site, among which His64, His94, His96, Val121, and Thr200. Fullerenes thus represent a totally new class of nanoscale CA inhibitors which may show applications for targeting physiologically relevant isoforms, such as the dominant CA II and the tumor-associated CA IX. © 2010 Elsevier Ltd. All rights reserved.

Jiang C.,Richard E Smalley Institute For Nanoscale Science And Technology | Saha A.,Richard E Smalley Institute For Nanoscale Science And Technology | Xiang C.,Richard E Smalley Institute For Nanoscale Science And Technology | Young C.C.,University of Connecticut | And 5 more authors.
ACS Nano | Year: 2013

The solubility of single-walled carbon nanotube (SWCNT) polyelectrolytes [K(THF)]nSWCNT in dimethyl sulfoxide (DMSO) was determined by a combination of centrifugation, UV-vis spectral properties, and solution extraction. The SWCNT formed a liquid crystal at a concentration above 3.8 mg/mL. Also, crown ether 18-crown-6 was found to increase the solubility of the SWCNT polyelectrolytes in DMSO. Raman spectroscopy and near-infrared (NIR) fluorescence analyses were applied to study the functionalization of SWCNTs. Small-diameter SWCNTs were found to be preferentially functionalized when the SWCNT polyelectrolytes were dispersed in DMSO. © 2013 American Chemical Society.

Zhang C.,Tianjin University | Yao J.,Applied Physics Program Through | Hauge R.H.,Richard E Smalley Institute For Nanoscale Science And Technology | Tour J.M.,Richard E Smalley Institute For Nanoscale Science And Technology | Tour J.M.,Rice University
Nature Communications | Year: 2011

The controllable and reversible modification of graphene by chemical functionalization can modulate its optical and electronic properties. Here we demonstrate the controlled patterning of graphane/graphene superlattices within a single sheet of graphene. By exchanging the sp3 C-H bonds in graphane with sp3 C-C bonds through functionalization, sophisticated multifunctional superlattices can be fabricated on both the macroscopic and microscopic scales. These patterns are visualized using fluorescence quenching microscopy techniques and confirmed using Raman spectroscopy. By tuning the extent of hydrogenation, the density of the sp 3 C functional groups on graphene's basal plane can be controlled from 0.4% to 3.5% with this two-step method. Using such a technique, which allows for both spatial and density control of the functional groups, a route to multifunctional electrical circuits and chemical sensors with specifically patterned recognition sites might be realized across a single graphene sheet, facilitating the development of graphene-based devices. © 2011 Macmillan Publishers Limited. All rights reserved.

Mukherjee A.,Richard E Smalley Institute For Nanoscale Science And Technology | Kang J.,Applied Physics Program | Kuznetsov O.,Applied Physics Program | Kuznetsov O.,Rice University | And 5 more authors.
Chemistry of Materials | Year: 2011

A facile route to water-soluble graphite nanoplatelets that uses graphite as the starting material is described. The method relies on the addition of phenyl radicals with subsequent sulfonation of the phenyl groups. Atomic force microscopy, high-resolution transmission electron microscopy, and scanning tunneling microscopy images show that a high degree of exfoliation occurs during the sulfonation step. The sheet resistance of the bulk films of the nanoplatelets prepared by vacuum filtration using an anodisc membrane was found to be 212 Ω/sq. © 2010 American Chemical Society.

Liao K.-S.,University of Houston | Wang J.,Trinity College Dublin | Fruchtl D.,Trinity College Dublin | Alley N.J.,University of Houston | And 9 more authors.
Chemical Physics Letters | Year: 2010

In order to merge complementary temporal and spatial nonlinear optical characteristics of Fullerene and carbon nanotubes, synthesis of double wall carbon nanotube-Fullerene hybrid was performed by covalently linking DWNT and C60 by amination reaction with polyethylenimine. DWNT-Fullerene hybrids were characterized by thermogravimetric analysis, UV-vis spectroscopy and transmission electron microscopy. Optical limiting performance of DWNT-Fullerene hybrids is superior to those of Fullerenes and SWNTs at the same level (∼80%) of transmission. Whereas nonlinear scattering is an evident mechanism, reverse saturable absorption from Fullerene moieties has significant contribution. Charge transfer between the DWNT and Fullerene moieties may play an important role of optical limiting. © 2010 Elsevier B.V. All rights reserved.

Maguire-Boyle S.J.,Richard E Smalley Institute For Nanoscale Science And Technology | Barron A.R.,Richard E Smalley Institute For Nanoscale Science And Technology
Journal of Membrane Science | Year: 2011

The fabrication of surface functionalized alumina fabric composite membranes using hydrophilic cysteic acid surface stabilized alumina nanoparticles (alumoxanes) have been investigated. Contact angle measurements for a range of carboxylic acids functionalized onto alumina coated silicon wafers was investigated to determine the functionalization that results in the most hydrophilic surface. Highly porous Nomex® fabric was utilized as a membrane support for an alumoxane nanoparticle derived membrane filter. The flux differentiation of heavy hydrocarbons from water, and the separation of oil/water emulsions were studied. Coating techniques utilizing pH control were investigated. Retention coefficients and flux values indicate that surface chemistry of the fabric may be altered by coating with chemically functionalized alumina nanoparticles to provide selective flow of water versus hydrocarbons. © 2011 Elsevier B.V.

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