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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680965
• 关键词: Novel; mechanisms; strain; energy; dissipation; 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.

韧性是一种高度理想的材料特性，结合了强度和断裂抗性。除了非常强大之外，艰难的材料还可以在破裂前会发生相当大的变形。正在进行的研究以创造艰难的材料导致了各种金属合金和工程复合材料的发展。但是，这些材料的韧性是通过有限数量的“韧性机制”来实现的，我们几十年来都知道其中的大多数。由于韧性是如此理想的材料特性，因此确定新的韧性机制可能会推动各种新的工程材料的发展。 **该研究计划的目的是通过研究出色的生物材料：胶原原纤维来识别新的韧性机制。胶原蛋白原纤维是人类和几乎所有其他动物中最常见和重要的结构生物材料。胶原蛋白原纤维是直径近1000倍的生物电缆，它是人头发。它们是赋予您的肌腱，韧带，骨骼，皮肤，动脉，心脏瓣膜，软骨等力量的力量。除了非常强壮之外，胶原蛋白原纤维也非常坚硬：比钢丝强约10倍。然而，尽管具有令人难以置信的材料特性，但尚未鉴定出在胶原纤维中起作用的加强机制。使用诸如透射电子显微镜之类的工具，最多可超过300,000倍的增强率，我们将尝试确定是什么使胶原蛋白纤维坚硬。在研究计划的第二部分中，我们将研究不同类型的胶原蛋白原纤维，以尝试确定：（i）如果某些原纤维比其他原纤维更难，并且（ii）如果是），则哪种结构特征占了这种差异。我们还将化学修饰胶原纤维，人为地连接或分解其中包含的胶原蛋白分子，以查看这些变化如何改变韧性。在本研究计划的最后一部分中，我们将使用我们在第一部分和第二部分中收集的信息来构建新的，高性能的可生物降解材料。我们将致力于建造新的绷带和伤口敷料，这些绷带和伤口敷料在涂抹时柔软且可弯曲，但随后硬化为下面的愈合组织提供了更高的保护。我们还将通过用矿物质浸入胶原蛋白原纤维来建造新的复合材料。我们将使用这些新的复合材料来开发新的可吸收外科植入物。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，被人体分解并吸收。组织工程师将能够利用我们的结果来改善其实验室肌腱，韧带，皮肤和动脉的机械性能。发现使这些工程组织变得更坚硬的方法将有助于将它们推向市场，从而使每年需要涉及人造或同种异体组织组织的手术的加拿大人受益。在得知胶原原纤维及其分子过载后发生了什么事后，医生和外科医生可能会想到更好的治疗扭伤和菌株的方法，或者可以加速结缔组织愈合的方法。最后，材料科学家也许能够使用我们发现的独特的韧性机制来开发各种新材料，以供日常使用。