
Biotechnology and Applied Biochemistry (2010) 55, (2935) (Printed in Great Britain)
Preparation, characterization and evaluation of a biopolymeric gold nanocomposite with antimicrobial activity
Munusamy Chamundeeswari*, S. S. Liji Sobhana†, Justin P. Jacob*, M. Ganesh Kumar†, M. Pandima Devi‡, Thotapalli P. Sastry†1 and Asit B. Mandal§
*St. Joseph's College of Engineering, Sholinganallur, Chennai 600 119, India, †Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai 600020, India, ‡Department of Biotechnology, SRM University, Kattankulathur, Chennai 603203, India, and §Central Leather Research Institute, Adyar, Chennai 600020, India
Key words: ampicillin, chitosan, gold nanoparticle, minimal inhibitory concentration (MIC).
Abbreviations used: AFM, atomic force microscopy; AuNp, gold nanoparticle; C-AuNp, chitosan-capped AuNp; C-AuNp-Amp, C-AuNp coupled with ampicillin; LB, Luria–Bertani; NB, nutrient broth.
1To whom correspondence should be addressed (email sastrytp@hotmail.com).
The present study describes the antimicrobial activity of C-AuNp-Amp (chitosan-capped gold nanoparticles coupled with ampicillin). C-AuNp-Amp was synthesized using the wet precipitation method and characterized using FTIR (Fourier-transform IR) spectroscopy and AFM (atomic force microscopy) techniques. The optimal level of ampicillin concentration that couples with the C-AuNp nanocomposite was determined by using UV–visible spectroscopy. The agar-well diffusion method was used to evaluate the antimicrobial activity, and the broth dilution assay was used to determine the MIC (minimum inhibitory concentration). The size of the ellipsoidal C-AuNp-Amp particles was found to be in the range of 50–100 nm. The FTIR spectrum confirms the bonding between amino groups of chitosan and carboxylic groups of ampicillin. The maximum coupling of ampicillin with C-AuNp was found to be 4.07 mg/10 ml. These results revealed the antimicrobial efficacy of C-AuNp-Amp and a 2-fold increase in activity was achieved when compared with that of free ampicillin. By reducing the antibiotic dosage to 50%, the side effects produced by antibiotics can be minimized.
Received 7 July 2009/23 October 2009; accepted 20 November 2009
Published as Immediate Publication 20 November 2009, doi:10.1042/BA20090198
© 2010 Portland Press Ltd
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