Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia.
J Mater Chem B. 2021 Mar 14;9(10):2532-2546. doi: 10.1039/d0tb02971h. Epub 2021 Mar 4.
Finding the right balance in mechanical properties and degradation rate of biodegradable materials for biomedical applications is challenging, not only at the time of implantation but also during biodegradation. For instance, high elongation at break and toughness with a mid-term degradation rate are required for tendon scaffold or suture application, which cannot be found in each alpha polyester individually. Here, we hypothesise that blending semi-crystalline poly(p-dioxanone) (PDO) and poly(lactide-co-caprolactone) (LCL) in a specific composition will enhance the toughness while also enabling tailored degradation times. Hence, blends of PDO and LCL (PDO/LCL) were prepared in varying concentrations and formed into films by solvent casting. We thoroughly characterised the chemical, thermal, morphological, and mechanical properties of the new blends before and during hydrolytic degradation. Cellular performance was determined by seeding mouse fibroblasts onto the samples and culturing for 72 hours, before using proliferation assays and confocal imaging. We found that an increase in LCL content causes a decrease in hydrolytic degradation rate, as indicated by induced crystallinity, surface and bulk erosions, and tensile properties. Interestingly, the noncytotoxic blend containing 30% PDO and 70% LCL (PDO3LCL7) resulted in small PDO droplets uniformly dispersed within the LCL matrix and demonstrated a tailored degradation rate and toughening behaviour with a notable strain-hardening effect reaching 320% elongation at break; over 3 times the elongation of neat LCL. In summary, this work highlights the potential of PDO3LCL7 as a biomaterial for biomedical applications like tendon tissue engineering or high-performance absorbable sutures.
在生物医学应用中，寻找具有适当机械性能和降解速率的可生物降解材料极具挑战性，不仅在植入时如此，在降解过程中也是如此。例如，用于肌腱支架或缝线应用的可生物降解材料需要具有中等降解速率、高断裂伸长率和韧性，但每种α聚酯都无法同时满足这些要求。在这里，我们假设将半结晶聚对二氧环己酮（PDO）和聚（丙交酯-己内酯）（LCL）以特定比例混合，将提高韧性，同时也能够定制降解时间。因此，我们制备了不同浓度的 PDO 和 LCL（PDO/LCL）共混物，并通过溶剂浇铸将其制成薄膜。我们在水解降解前后对新共混物的化学、热学、形态和机械性能进行了全面的表征。通过将小鼠成纤维细胞接种到样品上并培养 72 小时，然后进行增殖测定和共聚焦成像，来确定细胞性能。我们发现，随着 LCL 含量的增加，水解降解速率会降低，这表现为诱导结晶度、表面和体相侵蚀以及拉伸性能的降低。有趣的是，含有 30%PDO 和 70%LCL（PDO3LCL7）的非细胞毒性共混物导致 PDO 小液滴均匀分散在 LCL 基质中，并表现出定制的降解速率和增韧行为，具有显著的应变硬化效应，断裂伸长率达到 320%；比纯 LCL 高出 3 倍多。总之，这项工作强调了 PDO3LCL7 作为生物医学应用（如肌腱组织工程或高性能可吸收缝线）的生物材料的潜力。
