Green and safe preparation of antibacterial sutures composed of PLA ultrafine fibers

The electrospun yarn for sutures has gained worldwide attention due to its fine fibers that resemble the extracellular matrix and its abundant functional sites. However, the use of a large number of toxic solvents poses safety risks and environmental pollution during production, making it challenging to directly apply electrospun yarn in the biomedical field. In this study, an environmentally friendly and safe method without toxic solvents was proposed for preparing antibacterial PLA ultrafine fiber sutures. This method involves melt electrospinning, hot-stretching, low-temperature plasma treatment, and chitosan grafting. The PLA ultrafine fiber sutures exhibit a high tensile strength which is 2.04 N before knotting and 1.57 N after knotting. The suture diameter is 118.7 μm and average fiber diameter is 1.72 μm. Chitosan grafted on the fiber surface provides excellent antibacterial properties for the sutures, with antibacterial rates against Escherichia coli and Staphylococcus aureus reaching 99.89% and 99.11%, respectively. The cell survival rate is 97.33%, while hemolysis rate is only 2.35%, demonstrating excellent biocompatibility of PLA ultrafine fiber sutures. This study presents a green and safe method for preparing clinically applicable absorbable antibacterial surgical sutures with high mechanical properties. Highlights A green and safe method for preparing PLA-CS ultrafine fiber sutures. PLA-CS suture with a tensile strength of 2.04 N and a fiber diameter of 1.72 μm. PLA-CS suture with good antibacterial property and biocompatibility.