01665nas a2200241   4500008004100000022001400041245011200055210006900167260007300236300001200309490000600321520081500327653000801142653003901150653001901189653000801208100002001216700001401236700001601250700001401266700002401280856011901304       2005                        eng d  a1567-173900aDNA and PNA as templates for building nanoassemblies via electrostatic complexation with gold nanoparticles0 aDNA and PNA as templates for building nanoassemblies via electro  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a102-1070 v53 a<p>Organisation of nanoparticles on structurally well-defined templates is a first step towards creating nanomachines. In this respect, nucleic acids are ideal structural templates and a variety of secondary structures realizable from DNA/RNA - e.g., duplexes, hairpins, triplexes, cruciforms, tetraplexes can be exploited to engineer nanoparticle organization at will. We have used oligonucleotides and their analogues such as phosphorothioates and peptide nucleic acids to electrostatically encapsulate cationic-capped gold nanoparticles. This article describes synthesis and characterization of DNA/PNA-gold nanoparticle composites using TEM and UV-T-m techniques. These types of assemblies may have potential for creating nanowires and lithographic circuits. (C) 2004 Elsevier B.V. All rights reserved.</p>10aDNA10aDNA-gold nanoparticle interactions10ananoassemblies10aPNA1 aGourishankar, A1 aShukla, S1 aPasricha, R1 aSastry, M1 aGanesh, Krishna, N.  uhttps://library.ncl.res.in/content/dna-and-pna-templates-building-nanoassemblies-electrostatic-complexation-gold-002053nas a2200157   4500008004100000022001400041245009400055210006900149260006700218300001400285490000700299520144200306100001601748700001401764856011701778       2005                        eng d  a8756-793800aFree-standing nanogold membranes as supports for the growth of calcium phosphate crystals0 aFreestanding nanogold membranes as supports for the growth of ca  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcNOV  a1759-17670 v213 a<p>Current strategies for bone tissue regeneration focus on the development of implantable matrices that mimic biological tissues. Inorganic composites are of special interest for bone substitute applications. It is necessary to create an artificial three-dimensional scaffold-like porous material with certain geometrical structure to induce bone growth. We report here the growth of calcium phosphate crystals on free-standing carboxylic acid functionalized gold nanoparticle membranes. The gold nanoparticle membrane is synthesized by the spontaneous reduction of aqueous chloroaurate ions by a diamine molecule at a liquid-liquid interface. This membrane is robust and malleable, and most importantly, the gold nanoparticles in the membrane may be functionalized with suitable ligands. In this study, the amino acids aspartic acid and cysteine together with an aromatic bifunctional molecule, anthranilic acid, were used to modify the surface of the gold nanoparticles in the membrane. The free carboxylic acid groups on the gold nanoparticles further to functionalization with these molecules were then used to bind Ca2+ ions and reacted with phosphate ions to yield calcium phosphate. The nature of the nanogold surface modifier directed the formation of either crystalline hydroxyapatite or amorphous calcium phosphate. The nanogold membrane thus suggests potential biomedical application as biocompatible implants and grafts.</p>1 aRautaray, D1 aSastry, M  uhttps://library.ncl.res.in/content/free-standing-nanogold-membranes-supports-growth-calcium-phosphate-crystals-002039nas a2200217   4500008004100000022001400041245011900055210006900174260008600243300001000329490000700339520121600346653001701562653002301579653001801602653001801620100002501638700001701663700001401680856012701694       2005                        eng d  a1553-317400aGold nanotriangles biologically synthesized using tamarind leaf extract and potential application in vapor sensing0 aGold nanotriangles biologically synthesized using tamarind leaf   a325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USAbTAYLOR & FRANCIS INCcFEB  a19-260 v353 a<p>The size and shape dependent electronic and chemical properties of metal nanoparticles has drawn the attention of chemists, physicists, biologists, and engineers who wish to use them for the development of new generation nanodevices. In this article, we report the synthesis of gold nanotriangles using tamarind leaf extract as the reducing agent. On treating aqueous chloroauric acid solution with tamarind leaf extract, rapid reduction of the chloroaurate ions is observed leading to the formation of flat and thin single crystalline gold nanotriangles. Atomic force microscopy analysis of the gold nanotriangles indicated that they ranged in thickness from 20 to 40 nm. These gold nanotriangles with unique and highly anisotropic planer shapes might find application in photonics, optoelectronics, and optical sensing. We investigated the effect of different organic solvent vapors like methanol, benzene and acetone on the conductivity of tamarind leaf extract reduced gold nanotriangles. I-V characteristics measurement of these nanotriangles was done in presence of these organic solvent vapors. The observed characteristics suggest the application of gold nanotriangles to future chemical sensors.</p>10aBiosynthesis10agold nanotriangles10atamarind leaf10avapor sensing1 aAnkamwar, Balaprasad1 aChaudhary, M1 aSastry, M  uhttps://library.ncl.res.in/content/gold-nanotriangles-biologically-synthesized-using-tamarind-leaf-extract-and-potential-000879nas a2200145   4500008004100000022001400041245009700055210006900152260011000221300001400331520023100345100002000576700001400596856012300610       2005                        eng d  a1359-734500aHollow gold and platinum nanoparticles by a transmetallation reaction in an organic solution0 aHollow gold and platinum nanoparticles by a transmetallation rea  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcFEB  a1684-16863 aTransmetallation reaction between hydrophobized silver nanoparticles with hydrophobized chloroaurate and chloroplatinate ions in chloroform results in the formation of hollow gold and platinum shell nanoparticles respectively.1 aSelvakannan, PR1 aSastry, M  uhttps://library.ncl.res.in/content/hollow-gold-and-platinum-nanoparticles-transmetallation-reaction-organic-solution-002298nas a2200169   4500008004100000022001400041245016400055210006900219260007100288300001400359490000700373520157900380100001201959700001401971700001101985856013201996       2005                        eng d  a0006-296000aIllustration of HIV-1 protease folding through a molten-globule-like intermediate using an experimental model that implicates alpha-crystallin and calcium ions0 aIllustration of HIV1 protease folding through a moltenglobulelik  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a3725-37340 v443 a<p>The folding of HIV-1 protease to its active form involves the coordination of structure formation and dimerization, which follows a hierarchy consisting of folding nuclei spanning from the active site, hinge region, and dimerization domain. However, the biochemical characteristics of the folding intermediates of this protein remain to be elucidated. In an experimental model, the denaturation of the tethered dimer of HIV-1 protease by guanidine hydrochloride revealed an alternative conformation resembling the molten globule state. The molten-globule state binds to the molecular chaperone alpha-crystallin and prevents its aggregation; however, the chaperone alone failed to reconstitute HIV-1 protease into its active form. Calcium ion assisted in the release of active enzyme from the chaperone complex. alpha-crystallin, a member of the small heat-shock protein, assists proteins to fold correctly; however, the underlying principle of signals responsible for chaperone-mediated protein folding remains enigmatic. X-ray photoelectron spectroscopy has been employed to provide the evidence of calcium binding to alpha-crystallin and to decipher the effect of calcium binding on the chaperone-mediated refolding of HIV-1 protease. On the basis of our spectroscopic data, we propose that calcium ions interact with the carboxyl groups of the surface-exposed acidic amino acids of alpha-crystallin bringing electrostatic interference, which plays a pivotal role in inducing conformational changes in the chaperone responsible for the release of the active enzyme.</p>1 aDash, C1 aSastry, M1 aRao, M  uhttps://library.ncl.res.in/content/illustration-hiv-1-protease-folding-through-molten-globule-intermediate-using-experimental-002534nas a2200277   4500008004100000022001400041245007200055210006900127260009500196300001400291490000600305520159800311653003201909653001501941653003101956653001801987653002102005653002402026653001502050100001902065700002002084700001602104700001602120700001402136856010602150       2005                        eng d  a1533-488000aSynthesis of CdS and alloyed CdMnS nanocrystals using aqueous foams0 aSynthesis of CdS and alloyed CdMnS nanocrystals using aqueous fo  a25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USAbAMER SCIENTIFIC PUBLISHERScDEC  a2144-21540 v53 a<p>Certain surfactant-stabilized aqueous foams provide a potentially efficient and simple chemical route for the synthesis of various nanomaterials with controllable structure, size, and shape. In the present work, a one-step process for the synthesis of CdS and Cdl(1-x)Mn(x)S (0 &lt; x &lt; 10) nanocrystals has been described. Aqueous CdCl2 and the aerosol-OT solutions are homogeneously mixed together and thereafter, nitrogen is bubbled through this solution to produce stable aqueous foam. After drainage of the foam, the freestanding dry foam consisting of cadmium cations electrostatically complexed with the anionic aerosol-OT molecules at the liquid-gas interface is treated with H2S vapor. The foam turns yellowish-orange and collapses, in the process yielding CdS nanoclusters of variable morphology. This morphology variation is appropriately attributed to growth of the CdS as well as alloyed Cd1-xMnxS nanoparticles in different regions of the foam contributing to the varying topological structure. Optical absorption spectra of both CdS and Cd1-xMnxS nanoparticles clearly show a well-defined exciton absorption feature around 450 nm due to quantum confinement effects. The interesting band edge emission characteristics of these AOT-capped CdS and Cd1-xMnxS nanoparticles produced in the foam are discussed with respect to their size and shape. Particular interest in the present novel aqueous foam approach arises due to the fact that the cubic zincblende CdS and alloyed Cd1-xMnxS nanocrystals could easily be obtained even under ambient experimental conditions itself.</p>10aabsorption and fluorescence10aaerosol-OT10aalloyed CdMnS nanocrystals10aaqueous foams10aCdS nanoclusters10aquantum confinement10azincblende1 aKumar, Senthil1 aKasture, Manasi1 aRaghavan, U1 aPasricha, R1 aSastry, M  uhttps://library.ncl.res.in/content/synthesis-cds-and-alloyed-cdmns-nanocrystals-using-aqueous-foams-001826nas a2200169   4500008004100000022001400041245012900055210006900184260007100253300001600324490000800340520113300348100001601481700001301497700001401510856013201524       2005                        eng d  a1520-610600aTransmetalation reaction between hydrophobic silver nanoparticles and aqueous chloroaurate ions at the air - Water interface0 aTransmetalation reaction between hydrophobic silver nanoparticle  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT  a19620-196260 v1093 a<p>The transmetalation reaction between a sacrificial nanoparticle and more noble metal ions in solution has emerged as a novel method for creating unique hollow and bimetallic nanostructures. In this report, we investigate the possibility of carrying out the transmetalation reaction between hydrophobic silver nanoparticles assembled and constrained at the air-water interface and subphase gold ions. We observe that facile reduction of the subphase gold ions by the sacrificial silver nanoparticles occurs resulting in the formation of elongated gold nanostructures that appear to cross-link the sacrificial silver particles. This transmetalation reaction may be modulated by the insertion of an electrostatic barrier in the form of an ionizable lipid monolayer between the silver nanoparticles and the aqueous gold ions that impacts the gold nanoparticle assembly. Transmetalation reactions between nanoparticles constrained into a close-packed structure and appropriate metal ions could lead to a new strategy for metallic cross-linking of nanoparticles and generation of coatings with promising optoelectonic behavior.</p>1 aPasricha, R1 aSwami, A1 aSastry, M  uhttps://library.ncl.res.in/content/transmetalation-reaction-between-hydrophobic-silver-nanoparticles-and-aqueous-chloroaurate-002340nas a2200169   4500008004100000022001400041245012100055210006900176260011000245300001200355490000800367520162400375100001601999700001802015700001402033856012302047       2005                        eng d  a1364-549800aUsing the dynamic, expanding liquid-liquid interface in a Hele-Shaw cell in crystal growth and nanoparticle assembly0 aUsing the dynamic expanding liquidliquid interface in a HeleShaw  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN  a205-2170 v1293 a<p>The liquid-liquid interface has been used with considerable success in the synthesis of advanced materials ranging from (bio)minerals to inorganic membranes to nanoparticles. In almost all such cases, the interface is static. The Hele-Shaw cell in which a viscous fluid is displaced by a less viscous one in a constrained manner has been invaluable in the study of dynamic instabilities at interfaces and in the study of viscous fingering pattern formation. However, the potential of the Hele-Shaw cell in carrying out reactions at the interface between the two fluids leading to the formation of inorganic materials has been largely unrecognized and underexploited. Realizing that the dynamic liquid-liquid interface in a Hele-Shaw cell would provide opportunities to control a variety of time-scales associated with material formation, we have started a program on the use of the Hele-Shaw cell in materials synthesis. In this discussion paper, we present some of our recent results on the growth of calcium carbonate crystals in the Hele-Shaw cell by the reaction of Ca2+ ions electrostatically complexed with carboxylate ions pinned to the interface with carbonate ions present in the aqueous part of the biphasic reaction medium. We show that both polymorph selectivity and the morphology of the crystals may be modulated by varying the experimental conditions in the cell. We also discuss the possibility of using the dynamic interface in the Hele-Shaw cell to cross-link gold nanoparticles in water through bifunctional linkers present in the oil phase and investigate the nature of the structures formed.</p>1 aRautaray, D1 aKavathekar, R1 aSastry, M  uhttps://library.ncl.res.in/content/using-dynamic-expanding-liquid-liquid-interface-hele-shaw-cell-crystal-growth-and-0