Novel mechanisms of strain energy dissipation in collagen polymers: their characterization, control, and application

胶原聚合物应变能耗散的新机制：其表征、控制和应用

• 批准号: RGPIN-2014-04967
• 负责人: Veres, Samuel
• 金额: $ 1.82万
• 依托单位: Saint Mary's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=667728
• 关键词: Novel; mechanisms; strain; energy; dissipation

Toughness is a highly desirable material property, combining both strength and fracture resistance. In addition to being very strong, tough materials can also undergo considerable deformation before breaking. Ongoing research to create tough materials has led to the development of a wide variety of metallic alloys and engineered composites. However, the toughness of these materials is achieved through a limited number of "toughening mechanisms", most of which we have known about for decades. Because toughness is such a desirable material property, identifying new toughening mechanisms could drive the development of a wide range of new engineering materials. **The aim of this research program is to identify new toughening mechanisms by studying a remarkable biomaterial: the collagen fibril. Collagen fibrils are the most common-and important-structural biomaterial within humans and almost all other animals. Collagen fibrils are biological cables that are nearly 1000 times smaller in diameter than a human hair. They are what gives strength to your tendons, ligaments, bones, skin, arteries, heart valves, cartilage, and more. In addition to being very strong, collagen fibrils are also very tough: approximately 10 times tougher than steel wire. Yet, despite their incredible material properties, the toughening mechanisms that function within collagen fibrils have not yet been identified.**In the first part of this research program, the nanoscale structure of both collagen fibrils and the molecules that they are composed of will be studied before and after mechanical overload. Using tools such as transmission electron microscopy, with which magnifications of up to 300,000x are possible, we will attempt to determine what makes collagen fibrils tough. In the second part of the research program, we will study different types of collagen fibrils to try and determine: (i) if some fibrils are tougher than others, and (ii) if so, what structural characteristics account for this difference. We will also chemically modify collagen fibrils, artificially joining or breaking apart the collagen molecules contained within to see how these changes alter toughness. In the final part of this research program, we will use the information that we have gathered in parts one and two to build new, high-performance, biodegradable materials. We will work toward building new bandages and wound dressings that are soft and bendable when applied, but then harden giving superior protection to the healing tissue beneath. We will also work toward building new composite materials by impregnating collagen fibrils with minerals. We will use these new composite materials to develop new, resorbable surgical implants. For repairing a badly fractured bone, for example, a collagen-based implant could provide the structural support required during healing and then slowly disappear, being broken down and absorbed by the body.**While this work will take many years to complete, the results, even from the project's early stages, will be important to many people. Tissue engineers will be able to use our results to improve the mechanical performance of their laboratory-built tendons, ligaments, skin, and arteries. Discovering ways to make these engineered tissues tougher would help bring them to market, benefiting the thousands of Canadians each year who require surgeries involving artificial or allograft tissue. After learning what happens to collagen fibrils and their molecules when overloaded, doctors and surgeons may think of better ways to treat sprains and strains, or ways to accelerate connective tissue healing. And finally, material scientists may be able to use the unique toughening mechanisms that we discover to develop a whole range of new materials for everyday use.

韧性是一种非常理想的材料特性，结合了强度和抗断裂性。除了非常坚固之外，坚韧的材料在断裂之前也会经历相当大的变形。持续不断的制造坚韧材料的研究促进了多种金属合金和工程复合材料的开发。然而，这些材料的韧性是通过有限数量的“增韧机制”实现的，其中大多数机制我们已经了解了几十年。由于韧性是一种理想的材料特性，因此识别新的增韧机制可以推动各种新型工程材料的开发。 **该研究计划的目的是通过研究一种非凡的生物材料：胶原纤维来确定新的增韧机制。胶原原纤维是人类和几乎所有其他动物中最常见和最重要的结构生物材料。胶原纤维是一种生物纤维，其直径比人类头发丝小近 1000 倍。它们为肌腱、韧带、骨骼、皮肤、动脉、心脏瓣膜、软骨等提供力量。除了非常坚固之外，胶原纤维还非常坚韧：大约比钢丝坚韧 10 倍。然而，尽管它们具有令人难以置信的材料特性，但胶原纤维内发挥作用的增韧机制尚未确定。**在本研究计划的第一部分中，胶原纤维及其组成分子的纳米级结构将被确定。研究了机械过载之前和之后。使用透射电子显微镜等工具（放大倍数可达 300,000 倍），我们将尝试确定胶原纤维坚韧的原因。在研究计划的第二部分中，我们将研究不同类型的胶原原纤维，试图确定：（i）某些原纤维是否比其他原纤维更坚韧，以及（ii）如果是，是什么结构特征导致了这种差异。我们还将对胶原纤维进行化学修饰，人工连接或分解其中所含的胶原蛋白分子，以观察这些变化如何改变韧性。在本研究计划的最后部分，我们将利用第一部分和第二部分中收集的信息来构建新型高性能可生物降解材料。我们将致力于制造新的绷带和伤口敷料，这些绷带和伤口敷料在使用时柔软且可弯曲，但随后会变硬，为下面的愈合组织提供卓越的保护。我们还将致力于通过用矿物质浸渍胶原纤维来构建新型复合材料。我们将使用这些新型复合材料来开发新型可吸收外科植入物。例如，为了修复严重骨折的骨头，基于胶原蛋白的植入物可以提供愈合过程中所需的结构支撑，然后慢慢消失，被身体分解和吸收。**虽然这项工作需要很多年才能完成，但即使从项目的早期阶段来看，结果对许多人来说也很重要。组织工程师将能够利用我们的研究结果来改善实验室制造的肌腱、韧带、皮肤和动脉的机械性能。找到使这些工程组织变得更坚韧的方法将有助于将它们推向市场，从而使每年成千上万需要进行人造或同种异体移植组织手术的加拿大人受益。在了解胶原纤维及其分子在超负荷时会发生什么变化后，医生和外科医生可能会想到更好的方法来治疗扭伤和拉伤，或者加速结缔组织愈合的方法。最后，材料科学家也许能够利用我们发现的独特的增韧机制来开发一系列日常使用的新材料。