Preparation and characterization of chlorinated cross-linked chitosan/cotton knit for biomedical applications

A new cross-linked chitosan/cotton knit was prepared by the chlorination of chitosan under acidic conditions, and its active chlorine content, mechanical and antimicrobial properties, and rechargeability were characterized. The active chlorine content of the chitosan/cotton knit increased with the concentration of chitosan or sodium hypochlorite used for the treatment and showed a slight decrease upon repeated laundering. The cross-linked chitosan/cotton knit displays lower stress and higher strain than pristine cotton knit. The chlorination of the chitosan/cotton knit resulted in powerful antimicrobial activity against both gram-negative and gram-positive bacteria. For up to 30 days of storage the knit showed excellent rechargeability, taking up chlorine to nearly initial levels. Scanning electron microscope (SEM) observations indicated that chlorination did not cause the damage to the cross-linked chitosan/cotton knit.