@article { ISI:000232326700015, title = {Porous gold nanospheres by controlled transmetalation reaction: a novel material for application in cell imaging}, journal = {Chemistry of Materials}, volume = {17}, number = {20}, year = {2005}, month = {OCT}, pages = {5000-5005}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Hollow shell nanostructures have numerous potential applications due to their interesting optical and electronic properties, which can be tuned by varying their shape, size, and shell thickness. In this paper we describe a simple galvanic replacement reaction (transmetalation reaction) involving sacrificial silver nanoparticles and Au(III) ions using a dialysis membrane. The dialysis membrane acts as a partial barrier that provides excellent control over the kinetics of reaction. This process results in the formation of porous gold nanospheres that improve the fluorescence in cell staining by offering an enhanced surface area for binding of the fluorescent dye, propidium iodide (PI). Such porous nanostructures could be ideal candidates for applications such as catalysis, enzyme immobilization, and drug delivery.

}, issn = {0897-4756}, doi = {10.1021/cm051165f}, author = {Shukla, Sourabh and Priscilla, Anie and Banerjee, Meenal and Bhonde, Ramesh R. and Ghatak, J. and Satyam, P. V. and Sastry, Murali} } @article { ISI:000270471100021, title = {Porous anisotropic metal nanostructures through controlled transmetallation across a dialysis membrane}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {9}, number = {11}, year = {2009}, month = {NOV}, pages = {6401-6408}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Nanostructured metals with hollow interiors are of technological importance due to their unique optoelectronic properties and enhanced surface area. We describe herein, a novel method for the synthesis of anisotropic gold and palladium nanoparticles through a simple galvanic replacement reaction across a semi-permeable dialysis membrane. The control over the reaction kinetics achieved by the presence of membrane enables one to tune the bimetal composition, particle porosity and morphology. Rapid outward diffusion of silver ions generated from the sacrificial silver nanoparticles even at room temperatures prevents the precipitation of high quantities of silver chloride, thereby circumventing the need for product purification. The porous anisotropic nanostructures have potential applications in catalysis, cell imaging and therapeutics.

}, keywords = {Ag/Pd Nanostructures, Anisotropic Nanoparticles, Dialysis, Galvanic Replacement, Porous nanostructures, Silver Nanotriangles, Silver Nanowires, Transmetallation}, issn = {1533-4880}, doi = {10.1166/jnn.2009.1350}, author = {Shukla, Sourabh and Pasricha, Renu and Sastry, Murali} } @article { ISI:000275134900013, title = {Probing differential Ag+-nucleobase interactions with isothermal titration calorimetry (ITC): towards patterned DNA metallization}, journal = {Nanoscale}, volume = {1}, number = {1}, year = {2009}, month = {OCT}, pages = {122-127}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

DNA has been Successfully used as a scaffold for the fabrication of metallic nanowires, primarily based oil the electrostatic complexation and reduction of the metal cations on the negatively charged sugar-phosphate backbone. Here. we probe the differential binding affinities of nucleobases for silver ions using sensitive isothermal titration calorimetry (ITC) measurements of the reaction enthalpies, which go in order: C \> G \> A \>= T. Using the disparity between the interaction of cytosine (strong binding) and thymine (weak binding) with silver ions, we have successfully generated silver nanoparticle doublets and triplets on custom-made oligonucleotides, C-30-T-40-C-30 and C-20-T-20-C-20-T-20-C-20, respectively. Thus, it new and simple method of generating metallized DNA wires is presented, based entirely on the nucleotide sequence of DNA. The concept could be extended to other cations and complex DNA sequences in order to achieve intricately patterned DNA constructs.

}, issn = {2040-3364}, doi = {10.1039/b9nr00004f}, author = {Shukla, Sourabh and Sastry, Murali} }