Stabilization of gold nanoparticles by hydrophobically-modified polycations

K. C. Remant Bahadur, Santosh Aryal, Shanta Raj Bhattarai, Narayan Bhattarai, Chi Hun Kim, Hak Yong Kim

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Surface-modified gold nanoparticles have pronounced benefits in the biomedical field due to their significant interaction with delivery materials. In the present study we used hydrophobically-modified polycations (i.e., N-acylated chitosan) to stabilize gold nanoparticles. Aliphatic hydrophobic groups, having carbon chains of different lengths, were first grafted onto the backbone of chitosan by N-acylation with fatty-acid chlorides in order to increase its hydrophobicity. Gold nanoparticles stabilized with native chitosan and N-acylated chitosan were prepared by the graft-onto approach. Chemical modification and its quantification were studied by Fourier-transform infrared (FT-IR) spectroscopy. Further, the stabilized gold nanoparticles were characterized by different physico-chemical techniques such as UV-Vis, FT-IR, TEM, TGA and DLS. Spectral studies of gold nanoparticles show the backbone and the side chain functional groups of chitosan were not cleaved during the conjugation process. TEM observations revealed that the modified chitosan gold nanoparticles were well dispersed and spherical in shape with average size around 10-12 nm in triply-distilled water at pH 7.4, whereas the native chitosan gold nanoparticles appeared as clusters with 9.9 nm as average diameter and were dispersed only in dilute HCl. The size of modified chitosan gold nanoparticles varied depending on the length of grafting molecules.

Original languageEnglish (US)
Pages (from-to)579-589
Number of pages11
JournalJournal of Biomaterials Science, Polymer Edition
Issue number5
StatePublished - May 2006


  • Biomaterial
  • Chitosan
  • Gold nanoparticles
  • Polycation
  • Self-assembly

ASJC Scopus subject areas

  • Biophysics
  • Biomaterials


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