Preparation and antibacterial activity of chitosan derivative membrane complexation with iodine

Abstract

Hydroxypropyl chitosan biguanide hydrochloride (HPCGH) was synthesized through the method of “amino protection–graft reaction–deprotection”, the HPCGH membrane (HPCGH–PVP-M) was then prepared from a mixture of gelatin and polyvinylpyrrolidone (PVP), following that, the iodine membrane (HPCGH–PVP–I₂-M) was obtained via the adsorption of iodine in iodine alcohol solution. The properties of HPCGH–PVP–I₂-M were characterized by Fourier-transform infrared (FT-IR), ¹H-NMR, X-ray diffraction (XRD) as well as thermogravimetric analysis (DTG) studies. The investigation results suggest that HPCGH–PVP–I₂-M has a better amorphous structure and a better thermal stability compared to that of HPCGH–PVP-M. Investigations were carried out on the iodine content demonstrating that HPCGH–PVP-M has superior properties for the adsorption of iodine. The iodine release studies in this work showed that HPCGH–PVP–I₂-M emitted iodine slowly and kept the iodine for a long time, and that HPCGH–PVP–I₂-M had the property of sustained-release iodine, furthermore, the higher the temperature and the higher the iodine content, the faster the release of iodine was. It was also found that the antibacterial activity of HPCGH–PVP–I₂-M against E. coli and S. aureus was better than that of HPCGH–PVP-M and that the inhibition zone diameters increased with an increase in the amount of iodine. When the content of iodine was 16.02% and the temperature was 37 °C, the inhibition zone diameters of HPCGH–PVP–I₂-M against E. coli and S. aureus were approximately 28 ± 1 mm and 30 ± 1 mm, respectively, hence the significant antibacterial activity.