A novel solvent-extruded tacrolimus-eluting suture for attenuated inflammation and scarring in skin repair

This study aimed to design an absorbable suture that locally delivers the immunosuppressive agent, tacrolimus (FK506), to attenuate scar tissue formation by modulating inflammation. As the suture degrades, it releases FK506 directly into the repair site. The poly (l-lactide-co-caprolactone) (PLLA-PCL) polymer and 0.2 % wt FK506 were co-extruded using a solvent extrusion technique to generate the drug-eluting sutures. The properties of the generated sutures were assessed regarding FK506 release in vitro, wound closure in an in vivo murine model, murine skin histology for structural and inflammatory markers, and mechanical strength of both sutures and healed murine skin. The generated suture consistently released FK506 at ≤10 ng/day rates. Following annealing, the sutures retained 60 % of their anticipated tensile strength, exhibiting enhanced ductility. The histological examination and in vivo murine study indicated that wounds treated with FK506-eluting PLLA-PCL sutures produced a thinner epidermal layer, enhanced integrin β4 expression, increased keratinocyte presence, attenuated inflammation, and reduced scarring, demonstrating healed tissue improvements compared with those treated with the placebo, poly (glycolic-co-caprolactone) (PGCL), sutures. Mechanical evaluations of healed tissue indicated that drug-PLLA-PCL sutures did not reduce the mechanical strength of the skin compared to placebo PGCL sutures. The FK506-eluting PLLA-PCL sutures show promising results in advancing wound healing by offering targeted drug delivery. This innovative method can improve wound healing and provide a streamlined approach to scar management. Continued research, optimization, and broad-scale studies are needed to refine the manufacturing process and ensure that the properties of the suture meet clinical requirements.