Antimicrobial Functionalization of Composite Nanofibrous Yarns as Surgical Sutures

Antimicrobial drug-releasing sutures have the potential to minimize the risk of postoperative inflammation and infection development. Using such medical devices is patient-considerate and cost-effective, reducing the need for oral drug administration and secondary surgical interventions. Nowadays, antimicrobial coatings on surgical sutures exist, however, they typically provide short-term drug release with limited concentrations. In this study, alternating current electrospinning was utilized to produce pristine and chlorhexidine (CHX) loaded composite polycaprolactone nanofibrous yarns with a mechanically resistant polyamide 6 core. Production speed between 10 and 30 m/min resulted in varying linear densities of yarns inversely proportional to the production speed and consequently with different concentrations of CHX. A prolonged release lasting one month was achieved, attributed to the dual relaxation times. Morphological analyses showed a composite character of yarns with a uniform pristine or CHX-loaded fibrous envelope that was susceptible to enzymatic degradation. The yarns exhibited high porosity, exceeding values typical for conventional fibers and displayed mechanical properties compatible with thin monofilaments sutures. The estimated curvature and torsion of the fibers, combined with the nanofibrous envelope resulted in a 3D yarn structure that closely mimics the extracellular environment. The 3D nature of composite nanofibrous yarns together with adsorbed proteins supported fibroblast adhesion and proliferation indicating biocompatibility. Proposed composite nanofibrous yarns represent an alternative to conventional smooth dip-coated antimicrobial sutures.