title: Stabilization of gold nanoparticles by hydrophobically-modified polycations.
abstract: 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.
authors.affiliation: Department of Bio-Nanosystem Engineering, Chonbuk National University, Chonju 561-756, South Korea.
authors.forename: K C
authors.initials: KC
authors.lastname: Remant Bahadur
authors.forename: Santosh
authors.initials: S
authors.lastname: Aryal
authors.forename: Shanta Raj
authors.initials: SR
authors.lastname: Bhattarai
authors.forename: Narayan
authors.initials: N
authors.lastname: Bhattarai
authors.forename: Chi Hun
authors.initials: CH
authors.lastname: Kim
authors.forename: Hak Yong
authors.initials: HY
authors.lastname: Kim
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry; D004337:Drug Carriers; D006046:Gold / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry*; D000071228:Polyelectrolytes; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001672:Biocompatible Materials; D048271:Chitosan; D004337:Drug Carriers; D006046:Gold; D011073:Polyamines; D000071228:Polyelectrolytes