Electrospun robust, biodegradable, bioactive, and nanostructured sutures to accelerate the chronic wound healing

Abstract The design and development of advanced surgical sutures with appropriate structure and abundant bio-functions are urgently required for the chronic wound closure and treatment. In this study, an integrated technique routine combining modified electrospinning with hot stretching process was proposed and implemented to fabricate poly(L-lactic acid) (PLLA) nanofiber sutures, and the Salvia miltiorrhiza Bunge-Radix Puerariae herbal compound (SRHC) was encapsulated into PLLA nanofibers during the electrospinning process to enrich the biofunction of as-generated sutures. All the PLLA sutures loading without or with SRHC were found to exhibit bead-free and highly-aligned nanofiber structure. The addition of SRHC was found to have no significant influences on the fiber morphology, diameter, and the crystallinity of as-prepared PLLA sutures. Importantly, all the SRHC-contained PLLA nanofiber sutures possessed excellent tensile and knot strength, which were of significant importance for the surgical suture applications. Besides, the antioxidant and anti-inflammatory properties of these sutures obviously enhanced with the increasing of SRHC concentration. Furthermore, the in vitro cell tests illustrated that the high fiber orientation of the sutures was able to efficiently induce the human dermal fibroblasts (HDFs) to migrate in a rapid manner, and the sutures loaded with high content of SRHC could significantly promote the attachment and proliferation of HDFs in comparison. The in vivo diabetic mouse model experiments revealed that all the as-developed PLLA sutures could effectively close the wound, but the PLLA sutures containing high content of SRHC could dramatically promote the wound healing with high quality by shortening the healing time, improving the collagen deposition, neovascularization, and the regeneration of hair follicles, especially compared with commercial polyester (PET) suture. This study offers a simple and easily-handling strategy to develop robust, biodegradable, bioactive, and nanostructured PLLA sutures, which shows huge potential for the treatment of hard-to-heal diabetic wounds.