Preparation and properties of silk fabric grafted with ɛ-polylysine by tyrosinase

Silk fabrics were treated with tyrosinase then grafted by ɛ-polylysine (ɛ-PLL). The optimal enzymatic reaction condition was investigated through the test of enzymatic activity and consumption of dissolved oxygen concentration. Amino acid analysis and scanning electron microscope observation confirmed the grafting of ɛ-PLL onto the silk fabrics. The crease resistance of the grafted fabrics was increased. In particular, the wet wrinkle resistance property was improved. The strength of the grafted fabrics was nearly unchanged. The gas permeability and whiteness slightly decreased, which hardly has any impact on the wearability of the fabrics. The antibacterial test showed that the grafted silk fabric had an excellent resistant property to Staphylococcus aureus and Escherichia coli. The inhibition rate was about 90% after 30 times of washing, suggesting its potential application in antibacterial textiles and silk biomedical materials.