Development of an antibacterial chitin betainate wound dressing

Abstract

This research involved the chemical modification of chitin with positively charged groups to confer antibacterial activity. Chitin betainate, a quaternary ammonium chitin, was prepared by the acylation of chitin with carboxymethyl trimethyl ammonium chloride. The chemical structure was elucidated by Fourier transform infrared spectroscopy (FTIR), which revealed the presence of the additional ester peak at 1738 cm-1 and some change in amide I at 1650 cm-1. Chitin and chitin betainate gels were prepared and then tested for their water absorption, contact angle and antibacterial activity. The chitin betainate had a 1.07-fold higher water-absorption level and a higher hydrophilic property than chitin, and it also exhibited an antibacterial activity against Staphylococcus aureus and Escherichia coli. At a final concentration of 10 mg ml-1, chitin betainate completely killed E. coli within 10 min, and S. aureus was reduced by 45.2% and 78% after 10 min and 24 h, respectively. The antibacterial activity against S. aureus was dose-dependent, whereas no antibacterial activity was observed against E. coli when using chitin betainate at <10 mg ml-1. The addition of PEG4000 to either chitin or chitin betainate further increased the water absorption by 2.0-and 2.5-fold, respectively. Therefore, chitin betainate is expected to be suitable as an antibacterial wound-dressing material. © 2014 The Society of Polymer Science, Japan (SPSJ). All rights reserved.