A green approach for the preparation of antibacterial polylactide fabric via radiation-induced graft polymerization and copper complexation

Herein, we newly developed an eco-friendly and efficient strategy for antibacterial modification of PLA fabrics that facilitates manufacturing processing in an all-aqueous solution and ensures antibacterial activity without significant deterioration of the mechanical strength. The PLA fabrics were efficiently modified with covalent bonding through electron beam (EB)-induced aqueous graft polymerization of acrylic acid (AA) in the presence of a poly(ethylene glycol) diacrylate (PEGDA) crosslinker and then complexed with antibacterial copper (Cu) ions (PLA-g-cPAA-Cu). The addition of the PEGDA crosslinker (0.6 wt%) to the graft polymerization led to a nearly twofold increase in the grafting degree from 50 to 91 % in the water solvent in comparison to in the absence of PEGDA. The resulting grafted fabric also showed minimal deterioration of mechanical strength. It was further found that the hydrophilic PEGDA-crosslinked PAA-Cu complexes were incorporated mainly onto the surfaces of the fiber constituents, preserving the porous structure of the PLA fabric. The prepared PLA-g-cPAA-Cu fabrics with a grafting degree of above 20 % showed excellent contact-killing ability of 99.9 % for Gram-negative E. coli and Gram-positive S. aureus within 3 h and cell viability of above 90 % in a WST-1 cytotoxicity assay using a skin cell line, HaCaT. Moreover, the PLA-g-cPAA-Cu fabric with a grafting degree of 20 % was more than 90 % enzymatically degraded after 90 days. The obtained results unequivocally demonstrate that this EB-based functionalization strategy is not only environmentally friendly and efficient, but also yields PLA-based PPEs with exceptional antibacterial activity, good biodegradability, and suitable mechanical strength.