Schmidt Stephen J, Holt Brian D, Arnold Anne M, Sydlik Stefanie A
Carnegie Mellon University 4400 Fifth Ave Pittsburgh PA 15213 USA
RSC Adv. 2020 Feb 28;10(14):8548-8557. doi: 10.1039/c9ra10646d. eCollection 2020 Feb 24.
Traditional metal implants such as titanium, cobalt, and chromium have found wide utility in medicine; however, these come with a risk of toxicity. To overcome metal-related toxicity and enable degradability, polyesters including polycaprolactone (PCL), polylactic acid (PLA), and polyglycolic acid (PGA) show promise for the replacement of various biomedical applications of metals due to their accepted biocompatibility and FDA approval. However, polyesters are less stiff than their metallic counterparts, limiting their application to non-load bearing injury sites, such as fixation hardware for fingers. To improve mechanical properties, graphene oxide (GO)-polyester composites are a promising class of biodegradable scaffolds. Initial reports of these composites are encouraging, but mechanical properties still fall short. Traditional composites rely on non-covalent association between GO and the polyesters, which often leads to failure at the interface and weakens the overall strength of the material. Herein, we present a strategy for attachment of these FDA-approved polyesters onto a derivative of GO using a robust covalent bond. By covalently functionalizing the graphenic backbone with polyesters and without metal catalysts, we create functional graphenic materials (FGMs) to not only simultaneously retain biodegradability and compatibility, but also mechanically strengthen PCL, PLA, and PGA; we observed an average increase in the Young's modulus of over 140% compared to the graphenic backbone. These polyester-functionalized FGMs are a promising platform technology for tissue implants.
传统的金属植入物，如钛、钴和铬，在医学上有广泛的应用；然而，这些植入物存在毒性风险。为了克服与金属相关的毒性并实现可降解性，包括聚己内酯（PCL）、聚乳酸（PLA）和聚乙醇酸（PGA）在内的聚酯，因其公认的生物相容性和获得美国食品药品监督管理局（FDA）批准，有望替代金属在各种生物医学应用中的使用。然而，聚酯的硬度低于金属同类物，这限制了它们在非承重损伤部位的应用，例如手指固定器械。为了改善机械性能，氧化石墨烯（GO）-聚酯复合材料是一类有前景的可生物降解支架。关于这些复合材料的初步报告令人鼓舞，但机械性能仍有不足。传统复合材料依赖于GO与聚酯之间的非共价结合，这常常导致界面处失效并削弱材料的整体强度。在此，我们提出一种策略，使用牢固的共价键将这些经FDA批准的聚酯连接到GO的衍生物上。通过用聚酯对石墨烯主链进行共价功能化且不使用金属催化剂，我们创建了功能石墨烯材料（FGMs），不仅能同时保留生物降解性和相容性，还能在机械性能上增强PCL、PLA和PGA；与石墨烯主链相比，我们观察到杨氏模量平均提高了140%以上。这些聚酯功能化的FGMs是一种有前景的组织植入物平台技术。
