Astragaloside/PVP/PLA nanofiber functional dressing prepared by coaxial electrostatic spinning technology for promoting diabetic wound healing

Diabetic wound is often a chronic wound with complex healing process and long healing time. It is evident that conventional dressings are inadequate in promoting the healing of diabetic wounds. In this study, a novel nanofiber dressing, produced through coaxial electrostatic spinning technology, was created to facilitate the healing of diabetic chronic wounds. This dressing was composed of Astragaloside (AS), polyvinylpyrrolidone (PVP) and polylactic acid (PLA). The morphology of the nanofiber dressing was characterized by scanning electron microscopy (SEM). Confirmation of the core–shell structure was done with the help of transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). A pharmacodynamic study was conducted both in vivo and in vitro. It was shown that the nanofibers were approximately 604.83 ± 127.96 nm and with a core–shell structure. Additionally, in vitro drug release experiments revealed that the coaxial AS/PVP/PLA nanofiber functional dressings had a first rapid and then slow release property. Antioxidant activity experiment showed that the free radical scavenging rate of Astragaloside-loaded nanofibers reached 61 %. Mechanical tests also indicated that the nanofibers had an elastic modulus of 38.37 ± 1.81 MPa. Coaxial AS/PVP/PLA nanofiber functional dressings had good antimicrobial activity, and its diameter of the circle of inhibition against Staphylococcus aureus was 17.17 ± 2.04 mm, and its diameter of the circle of inhibition against Escherichia coli was 6.80 ± 0.78 mm. In addition, the findings of in vitro cellular tests showed that coaxial AS/PVP/PLA nanofiber functional dressings could promote the multiplication, adhesion and the migration ability of L929 fibroblasts with better biocompatibility. Finally, the wound healing rate of diabetic rats in the coaxial AS/PVP/PLA nanofiber functional dressing group was 96.54 ± 0.29 % on day 14. Consequently, the coaxial AS/PVP/PLA nanofiber functional dressings prepared by coaxial electrostatic spinning technique had satisfactory morphology, met the requirements of performance, and had the potential to be developed as a dressing for improving diabetic chronic wound healing.