Antibacterial and Physiochemical Behavior of Prepared Chitosan/pyridine-3,5-di-carboxylic Acid Complex for Biomedical Applications

Abstract

This paper describes the preparation of a biocompatible electrostatic chitosan/pyridine-3,5-di-carboxylic acid (CH-PyCA) complex which is formed by the protonation (NH⁺ ₃) of chitosan and deprotonation (COO⁻) of pyridine-3,5-di-carboxylic acid in an acidic medium under mild conditions. The crystalline and structural properties of prepared CH-PyCA complex were evaluated by UV, IR XRD and ¹H-NMR spectroscopic studies. Thermal behavior of the complex was evaluated by differential scanning calorimetry (DSC) and thermogravimetry (TG). Antimicrobial activities examined against gram-positive bacteria (Listeria monocytogenes) and gram-negative bacteria (Escherichia coli) by agar diffusion plate method in the obtained CH-PyCA complex, were found to be much better than free chitosan and pyridine compounds and the obtained results indicate that the inhibitory effects of chitosan complex is dependent on the molecular weight, ionic strength, pH, and the degree of deacetylation of chitosan. The results show that the CH-PyCA complex might be a promising candidate for novel antimicrobial agents for biomedical applications.

Keywords:

• Chitosan
• pyridine-3,5-di-carboxylic acid
• chitosan complex
• antibacterial activity

Acknowledgments

We thank CSIR and UGC New Delhi, and Royal Society of Chemistry for Research Fund Grants and Dr. G. K. Mehrotra, Assistant Professor of MNNIT for reviewing the paper.