Composite yarns with antibacterial nanofibrous sheaths produced by collectorless alternating-current electrospinning for suture applications

Fabrication of strong antibacterial composite nanofibrous yarns (CNYs) for suture applications by using common direct current electrospinning has been technologically challenging. In this work, we have demonstrated a more straightforward and facile approach to fabricate chlorhexidine (CHX)-containing antibacterial nanofibrous sheaths wounded around a polyamide core yarn using a novel collectorless alternating-current electrospinning approach. Scanning electron microscopy results showed that the nanofibrous envelope was completely wrapped around the core yarn for both polymers, polyurethane, and polyamide 6 (PA6), used in this study. High-performance liquid chromatography after dissolving of the CNYs confirmed the presence of CHX in the yarns, while X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy indicated that the amount is relatively low. The tensile properties of all the CNYs were better than of the core yarns and the CHX addition resulted in a lower envelope linear density and envelope adhesion force. Thermal gravimetric analysis showed that all CNYs are thermally stable within the temperature range of interest. Cytocompatibility tests with 3T3-SA mouse fibroblast cells and antibacterial evaluations with Escherichia coli and Staphylococcus aureus showed that the CHX-containing PA6-based CNYs are biocompatible and have antibacterial properties, suggesting that these yarns can be used as functional and mechanically performant sutures.