Preparation and Characterization of Gold Nanoparticles in Chitosan Suspension by One-Pot Chemical Reduction Method

R Lakshmi Narayanan,M Sivakumar

doi:10.4028/www.scientific.net/nh.6.47

R Lakshmi Narayanan, M Sivakumar

Open Access

https://doi.org/10.4028/www.scientific.net/nh.6.47

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Journal: Nano Hybrids	Publication Date: Feb 1, 2014
Citations: 13	License type: CC BY 4.0

Affiliation: Anna University, Chennai

Abstract

Gold nanoparticles were synthesized in chitosan suspension by one-pot chemical reduction method without any chemical reducing reagent. In aqueous acidic medium, chitosan exhibits polycationic nature due to protonation of amine groups of each glucosamine repeating units. The adsorption of AuCl4- ions occurs on chitosan through electrostatic attraction and further reduction of Au3+ to Au0 proceeds through a three electron transfer mechanism by oxidation of protonated amine groups of chitosan chain. The change of color from dirty yellow to intense red indicates the formation of gold nanoparticles in chitosan suspension which acts as both reducing and stabilizing agent. Characterization techniques such as UV-VIS, FTIR, Zeta potential measurement, FESEM and TEM were carried out in order to examine the reduction and stabilization phenomena rendered by chitosan.

Highlights

Chitin and Chitosan are described as a family of linear polysaccharides consisting of varying amounts of β(1 - 4) linked residues of N-acetyl-2-amino-2-deoxy-D-glucose and 2-amino-2-deoxyD-glucose residues which is called as N-acetyl glucosamine and glucosamine residues respectively
Adsorbed gold (III) ions on various chitosan chains get reduced to neutral gold atoms through oxidation of three protonated amine groups without influence of external chemical reagent and further agglomerates to form gold nanoparticles
Protonated amine groups of chitosan chain after reducing Au3+ ions gets conjugated to gold nanoparticle surface through Au-N bond formation which is already confirmed through FTIR studies

Summary

Introduction

Chitin and Chitosan are described as a family of linear polysaccharides consisting of varying amounts of β(1 - 4) linked residues of N-acetyl-2-amino-2-deoxy-D-glucose and 2-amino-2-deoxyD-glucose residues which is called as N-acetyl glucosamine and glucosamine residues respectively. Chitosan exhibits polyelectrolyte behaviour due to protonated amine groups which can reduce gold precursors and stabilize the formed gold nanoparticles [2].

Results

Conclusion