creators_name: Wangoo, Nishima
creators_name: Bhasin, K K
creators_name: Mehta, S K
creators_name: Suri, C Raman
type: article
datestamp: 2011-12-08 19:38:51
lastmod: 2011-12-08 19:38:51
metadata_visibility: show
title: Synthesis and capping of water-dispersed gold nanoparticles by an amino acid: bioconjugation and binding studies.
ispublished: pub
subjects: QR
full_text_status: restricted
note: Copyright of this article belongs to Elsevier Science
abstract: We report a novel strategy for the synthesis of aqueous stable, carboxylated gold nanoparticles (GNPs) by using glutamic acid as the reducing agent. The ratio of chloroaurate ions, AuCl(-)(4) to glutamic acid was optimized in the reaction medium to obtain monodispersed GNPs. Glutamic acid reduced gold nanoparticles were characterized by UV-visible, FTIR, dynamic light scattering and transmission electron microscopy, which demonstrated high stability in aqueous solution over a period of time indicating stabilization via surface-bound amino acid. Functionalized nanoparticles were conjugated with protein molecules through electrostatic attraction between the surface-terminated negatively charged carboxylate groups (COO(-)) of glutamic acid and the positively charged amino groups (NH(+)(3)) of the protein. The conjugation efficiency of the GNP:protein conjugates was confirmed qualitatively and quantitatively through gel electrophoresis and critical flocculation concentration analysis. The interaction between functionalized GNPs with protein molecules was investigated using fluorescence spectroscopy showing the fluorescence quenching of the tryptophan residues of protein molecules after conjugation. Circular dichroism (CD) studies of the conjugates confirmed that the protein undergoes a more flexible conformational state on the boundary surface of GNPs after conjugation. There was substantial conformational transition from alpha-helix to beta-sheet structure after conjugation of protein to GNPs.
date: 2008-07-15
date_type: published
publication: Journal of colloid and interface science
volume: 323
number: 2
publisher: Elsevier Science
pagerange: 247-54
refereed: TRUE
issn: 0021-9797
official_url: http://www.sciencedirect.com/science/article/pii/S0021979708004578
related_url_url: http://www.sciencedirect.com/science/article/pii/S0021979708004578
related_url_type: pub
citation:   Wangoo, Nishima and Bhasin, K K and Mehta, S K and Suri, C Raman  (2008) Synthesis and capping of water-dispersed gold nanoparticles by an amino acid: bioconjugation and binding studies.  Journal of colloid and interface science, 323 (2).  pp. 247-54.  ISSN 0021-9797     
document_url: http://crdd.osdd.net/open/592/1/suri08.2.pdf