Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom.
Tissue Eng Part A. 2024 Mar;30(5-6):214-224. doi: 10.1089/ten.TEA.2023.0273. Epub 2024 Jan 30.
Many surgical tendon repairs fail despite advances in surgical materials and techniques. Tendon repair failure can be partially attributed to the tendon's poor intrinsic healing capacity and the repurposing of sutures from other clinical applications. Electrospun materials show promise as a biological scaffold to support endogenous tendon repair, but their relatively low tensile strength has limited their clinical translation. It is hypothesized that combining electrospun fibers with a material with increased tensile strength may improve the suture's mechanical properties while retaining biophysical cues necessary to encourage cell-mediated repair. This article describes the production of a hybrid electrospun-extruded suture with a sheath of submicron electrospun fibers and a core of melt-extruded fibers. The porosity and tensile strength of this hybrid suture is compared with an electrospun-only braided suture and clinically used sutures Vicryl and polydioxanone (PDS). Bioactivity is assessed by measuring the adsorbed serum proteins on electrospun and melt-extruded filaments using mass spectrometry. Human hamstring tendon fibroblast attachment and proliferation were quantified and compared between the hybrid and control sutures. Combining an electrospun sheath with melt-extruded cores created a hybrid braid with increased tensile strength (70.1 ± 0.3N) compared with an electrospun only suture (12.9 ± 1 N, < 0.0001). The hybrid suture had a similar force at break to clinical sutures, but lower stiffness and stress. The Young's modulus was 772.6 ± 32 MPa for the hybrid suture, 1693.0 ± 69 MPa for PDS, and 3838.0 ± 132 MPa for Vicryl, < 0.0001. Hybrid sutures had lower overall porosity than electrospun-only sutures (40 ± 4% and 60 ± 7%, respectively, = 0.0018) but had a significantly larger overall porosity and average pore diameter compared with surgical sutures. There were similar clusters of adsorbed proteins on electrospun and melt-extruded filaments, which were distinct from PDS. Tendon fibroblast attachment and cell proliferation on hybrid and electrospun sutures were significantly higher than on clinical sutures. This study demonstrated that a bioactive suture with increased tensile strength and lower stiffness could be produced by adding a core of 10 μm melt-extruded fibers to a sheath of electrospun fibers. In contrast to currently used sutures, the hybrid sutures promoted a bioactive response: serum proteins adsorbed, and fibroblasts attached, survived, grew along the sutures, and adopted appropriate morphologies.
尽管在外科材料和技术方面取得了进步，但许多外科肌腱修复仍以失败告终。肌腱修复失败的部分原因是肌腱内在愈合能力差，缝线重新用于其他临床应用。静电纺丝材料作为一种支持内源性肌腱修复的生物支架具有很大的应用前景，但由于其拉伸强度相对较低，限制了其在临床上的应用。本研究假设，将静电纺丝纤维与具有增加的拉伸强度的材料结合使用，可以改善缝线的机械性能，同时保留促进细胞介导修复的生物物理线索。本文描述了一种具有亚微米静电纺丝纤维鞘和熔融纺丝纤维芯的混合静电纺丝-挤出缝线的制备方法。与纯静电纺丝编织缝线以及临床上使用的缝线 Vicryl 和聚二氧杂环己酮（PDS）相比，比较了这种混合缝线的孔隙率和拉伸强度。使用质谱法测量静电纺丝和熔融纺丝纤维上吸附的血清蛋白来评估生物活性。比较了混合缝线和对照缝线之间人半腱肌腱成纤维细胞的附着和增殖。与纯静电纺丝缝线相比，将静电纺丝鞘与熔融纺丝芯结合在一起可制成具有更高拉伸强度的混合编织缝线（70.1±0.3N）（<0.0001）。混合缝线的断裂力与临床缝线相似，但刚度和应力较低。混合缝线的杨氏模量为 772.6±32MPa，PDS 为 1693.0±69MPa，Vicryl 为 3838.0±132MPa（<0.0001）。与纯静电纺丝缝线相比，混合缝线的整体孔隙率较低（分别为 40±4%和 60±7%，=0.0018），但与手术缝线相比，混合缝线的整体孔隙率和平均孔径明显更大。静电纺丝和熔融纺丝纤维上吸附的蛋白质具有相似的蛋白簇，与 PDS 明显不同。混合缝线和静电纺丝缝线的肌腱成纤维细胞附着和细胞增殖明显高于临床缝线。本研究表明，通过在静电纺丝纤维护套中添加 10μm 熔融纺丝纤维芯，可以制备出具有增加的拉伸强度和较低的刚度的生物活性缝线。与目前使用的缝线不同，混合缝线促进了生物活性反应：吸附了血清蛋白，成纤维细胞附着、存活、沿缝线生长，并采用了适当的形态。
