Preparing chito-oligosaccharides as antimicrobial agents for cotton

Cotton fabric with good antimicrobial activity and durability to washing is obtained by using chito-oligosaccharides without the need for a binding ch emical as a crosslinker. The fully deacetylated chitosan is depolymerized i nto chito-oligosaccharide using sodium nitrite. The average degree of polym erization (DP) of chito-oligosaccharide is determined by colorimetric titra tion of a terminal aldehyde group of chito-oligosaccharide. In a pad-dry-cu re process, two different chito-oligosaccharides (DP = 3 and 10) are applie d to cotton fabric using the chemical reactivity of the terminal aldehyde g roup. The antimicrobial activity and durability to washing of the treated c otton an evaluated. The results show that at the fiftieth wash cycle, the c otton fabrics treated with 2.4% chito-oligosaccharide are able to maintain 95% (for a DP of 3) and 100% (for a DP of 10) bacterial reductions.