@conference { ISI:000245886300024, title = {Novel method for the synthesis of siloxane nanowires and filaments using gold nanoparticle catalysts}, booktitle = {International Conference on Nanoscience and Technology}, series = {International Journal of Nanoscience Series}, volume = {4}, number = {5-6}, year = {2005}, note = {International Conference on Nanoscience and Technology, Calcutta, INDIA, DEC 17-20, 2003}, month = {DEC}, pages = {1007-1010}, publisher = {World Scientific Publ Co Pte Ltd, Po Box 128 Farrer Rd, Singapore 9128, Singapore}, organization = {World Scientific Publ Co Pte Ltd, Po Box 128 Farrer Rd, Singapore 9128, Singapore}, address = { Calcutta, India}, abstract = {

A unique polymerization reaction of alkylsilanes to siloxane nanowires, filaments and tubes in presence of gold nanoparticles and water is presented. The gold nanoparticles, which catalyze this reaction also work as templates restricting the shape of the resulting polymers into wires and tubes. High resolution transmission electron microscopy images clearly reveal the presence of gold nanoparticle at the tip of each wire supporting the template hypothesis. Elemental analyses by different methods confirm the stoichiometry to be C18H37SiO1.5, when the alkylsilane used was C18H37SiH3, thus proving that the alkyl group remains intact during the polymerization reaction.

}, keywords = {gold nanoparticles, Nanowires, siloxane polymers}, doi = {10.1142/S0219581X0500398X}, author = {Bhagavatula L. V. Prasad and Stoeva, S. and Sorensen, C. M. and Klabunde, Kenneth J. and Zaikovskii, V.}, editor = {Sanyal, M. K. and Raychaudhuri, A. K. and Chakravorty, D.} } @article { ISI:000249838300014, title = {Nearly complete oxidation of Au(0) in hydrophobized nanoparticles to Au(3+) ions by N-bromosuccinimide}, journal = {Journal of Physical Chemistry C}, volume = {111}, number = {39}, year = {2007}, month = {OCT}, pages = {14348-14352}, publisher = {AMER CHEMICAL SOC}, type = {article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Au degrees atoms in hydrophobized gold nanoparticles were oxidized to Au(3+) ions, nearly quantitatively, simply by treatment with N-bromosuccinimide and sonication. (1)H NMR results indicate that the octadecylamine molecules are detached from the Au degrees surface by NBS. The bromine molecules released by NBS are suggested to be the species responsible for the oxidation of Au degrees to Au(3+), which is supported by the observation that addition of molecular bromine also leads to similar results. A gratifying feature is that the Au(3+) ions could be subsequently reduced back to An nanoparticles.

}, issn = {1932-7447}, doi = {10.1021/jp073717i}, author = {Singh, Sanjay and Bhagavatula L. V. Prasad} } @article { ISI:000261559400012, title = {Natural gum reduced/stabilized gold nanoparticles for drug delivery formulations}, journal = {Chemistry-A European Journal}, volume = {14}, number = {33}, year = {2008}, month = {OCT}, pages = {10244-10250}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

{\textquoteleft}{\textquoteleft}Gellan Gum{\textquoteright}{\textquoteright}, widely used in food and confectionary industry as a thickening and gelling agent, has been employed as a reducing and stabilizing agent for the synthesis of gold nanoparticles. These nanoparticles display greater stability to electrolyte addition and pH changes relative to the traditional citrate and borohydride reduced nanoparticles. Subsequently these have been used to load anthracycline ring antibiotic doxorubicin hydrochloride. The drug loaded on these nanoparticles showed enhanced cytotoxic effects on human glioma cell lines LN-18 and LN-229.

}, keywords = {Apoptosis, Cytotoxicity, drug delivery, Gold, Nanostructures, natural gums}, issn = {0947-6539}, doi = {10.1002/chem.200801093}, author = {Dhar, Sheetal and Reddy, E. Maheswara and Shiras, Anjali and Pokharkar, Varsha and Bhagavatula L. V. Prasad} } @article { ISI:000281058900005, title = {Nanogold-Loaded sharp-edged carbon bullets as plant-gene carriers}, journal = {Advanced Functional Materials}, volume = {20}, number = {15}, year = {2010}, month = {AUG}, pages = {2416-2423}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

The higher DNA delivery efficiency into plants by gold nanoparticles embedded in sharp carbonaceous carriers is demonstrated. These nanogold-embedded carbon matrices are prepared by heat treatment of biogenic intracellular gold nanoparticles. The DNA-delivery efficiency is tested on a model plant, Nicotiana tabacum, and is further extended to the monocot, Oryza sativa, and a hard dicot tree species, Leucaena leucocephala. These materials reveal good dispersion of the transport material, producing a greater number of GUS foci per unit area. The added advantages of the composite carrier are the lower plasmid and gold requirements. Plant-cell damage with the carbon-supported particles is very minimal and can be, gauged from the increased plant regeneration and transformation efficiency compared with that of the commercial micrometer-sized gold particles. This is ascribed to the sharp edges that the carbon supports possess, which lead to better piercing capabilities with minimum damage.

}, issn = {1616-301X}, doi = {10.1002/adfm.200901883}, author = {Vijayakumar, Periyasamy S. and Othalathara U. Abhilash and Khan, Bashir Mohammad and Bhagavatula L. V. Prasad} } @article { ISI:000332061300050, title = {Nanocomposite of silver and thermo-associating polymer by a green route: a potential soft-hard material for controlled drug release}, journal = {RSC Advances}, volume = {4}, number = {20}, year = {2014}, month = {JAN}, pages = {10261-10268}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Major research efforts are continuously being made to look for alternative, environment friendly green chemicals for the synthesis of nanoparticles in place of conventional and hazardous reducing agents such as sodium borohydride and hydrazine. We report here on the synthesis and characterization of AgNPs using a thermo-associating polymer namely, carboxymethyl guar grafted poly(ethylene oxide-co-propylene oxide) [CMG-g-PEPO]. The polymer acts as both reducing agent as well as stabilizing/capping agent. The formation of AgNPs with polymer was confirmed by UV/Vis spectroscopy and the TEM images indicated the size of nanoparticles to be in the range of 10-20 nm. We also demonstrated the use of these nanoparticles in the controlled release of doxorubicin hydrochloride (Dox), an anticancer drug. The binding of Dox onto the polymer and AgNPs was investigated by XPS and Raman spectroscopy which indicates that a charge-transfer mechanism is operative between the Dox and polymer holding both the entities together. The first synthesis of AgNPs using non-toxic thermo-associating polymer and subsequent release of Dox with body temperature (37 degrees C) as a trigger is the highlight of the present work.

}, issn = {2046-2069}, doi = {10.1039/c3ra45022h}, author = {Gupta, Nivika R. and Bhagavatula L. V. Prasad and Gopinath, Chinnakonda S. and Badiger, Manohar V.} }