Electrospun Heparin‐Loaded Core–Shell Nanofiber Sutures for Achilles Tendon Regeneration In Vivo

Abstract

Achilles tendon reconstruction surgery is the primary clinical method for repairing acute Achilles tendon ruptures. However, the efficacy of the postoperative healing process and the recovery of physiological function are inadequate. This study examines the healing mechanism of ruptured rat Achilles tendons seamed with heparin-loaded core-shell fiber sutures fabricated via near-field electrospinning. High-heparin-concentration sutures (PPH3.0) perform better than the low-heparin-concentration sutures and commercial sutures (CSs). The PPH3.0 suture recruits fewer inflammatory cells and shows good histocompatibility in peritoneal implantation experiments. Staining of the Achilles tendon rupture repair zone demonstrates that a high heparin concentration in sutures reduces immune-inflammatory responses. Immunohistochemical analysis reveals that the transforming growth factor-β staining scores of the PPH3.0 sutures are not significantly different from those of the corresponding control group but are significantly different from those of the CSs and non-heparin-loaded-suture groups. According to vascular endothelial growth factor (VEGF) analysis, the concentration of VEGF in the group treated with the PPH3.0 suture increases by 37.5% compared with that in its control group. No significant difference in tension strength is observed between the PPH3.0 group and healthy Achilles tendons. These findings illustrate that this novel method effectively treats Achilles tendon rupture and promotes healing and regeneration.

Electrospun Nanofibers for Tissue Engineering with Drug Loading and Release

“…A desirable scaffold that possesses both suitable mechanical properties and biological signals is required for tendon tissue engineering [80]. In recent years, novel spinning approaches were used to fabricate scaffolds mimicking the hierarchical structures of natural tendon tissue [81,82], and to accelerate the healing of tendon defects and further induce tendon regeneration. In addition to varying the preparation method, tendon scaffolds containing various bioactive molecules were also fabricated [83,84].…”

State-of-the-art review of advanced electrospun nanofiber yarn-based textiles for biomedical applications

“…Recently, to address this issue, several studies have been performed in innovative directions for employing electrospun NYs with great ECM fibril-mimicking characteristics as surgical sutures. From the perspective of suture composition, several absorbent synthesized polymers, such as PLGA [141] , PLLA [142] , PPDO [143] , and PCL [144] , were preliminarily investigated to electrospin them into NYs for surgical suture applications. It was found that the single electrospun NYs exhibited relatively low mechanical properties, which could not satisfy the requirements of practical applications [141] .…”

“…The results showed that the electrospun nanofibrous suture exhibited negligible immunogenicity, and significantly higher neovascularization was found in the nanofibrous suture than in the commercial microfibrous suture control. Several other studies reported the fabrication of electrospun nanofiber-coverspun yarns to enhance the mechanical properties of as-generated sutures [ 142 , 144 , 145 ].…”

“…The application of electrospun NYs as surgical sutures can address these problems well. For example, a variety of bioactive materials, such as curcumin [ 142 , 144 , 145 ], vascular endothelial growth factor (VEGF) [142] , aceclofenac [145] , insulin [145] , antimicrobial additives containing cefazolin [148] , and silver nanoparticles [149] , and biofunctional materials, i.e, carbon quantum dots [150] , were incorporated into the nanofibers in NYs to exert predetermined biological functions during electrospinning. A schematic explanation about the release of heparin from electrospun NYs is shown in Fig.…”

“…A schematic explanation about the release of heparin from electrospun NYs is shown in Fig. 10 A [142] . The growth factors and drugs exhibited sustained release behaviors when incorporated within electrospun NYs.…”