The antimicrobial activity of cotton fabrics treated with different crosslinking agents and chitosan

Cotton fabrics were treated with two different crosslinking agents [butanetetracarboxylic acid (BTCA) and Arcofix NEC (low formaldehyde content)] in the presence of chitosan to provide the cotton fabrics a durable press finishing and antimicrobial properties by chemical linking of chitosan to the cellulose structure. Both type and concentration of finishing agent in the presence of chitosan as well as the treatment conditions significantly affected the performance properties and antimicrobial activity of treated cotton fabrics. The treated cotton fabrics showed broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria and fungi tested. Treatment of cotton fabrics with BTCA in the presence of chitosan strengthened the antimicrobial activity more than the fabrics treated with Arcofix NEC. The maximum antimicrobial activity was obtained when the cotton fabrics were treated with 0.5-0.75% chitosan of molecular weight 1.5-5 kDa, and cured at 160 °C for 2-3 min. Application of different metal ions to cotton fabrics treated with finishing agent and chitosan showed a negligible effect on the antimicrobial activity. Partial replacement of Arcofix NEC with BTCA enhanced antimicrobial activity of the treated fabrics in comparison with that of Arcofix NEC alone. Transmission electron microscopy showed that the exposure of bacteria and yeast to chitosan treated fabrics resulted in deformation and shrinkage of cell membranes. The site of chitosan action is probably the microbial membrane and subsequent death of the cell.