Collaborative Research: Bone as an interpenetrating composite material

摘要：该项目由伊利诺伊大学厄巴纳- champion分校和加州大学圣地亚哥分校材料研究部生物材料项目授予，旨在研究一种新的骨模型，即骨中的两相，蛋白质和矿物质相互渗透（连续），并探索这一假设对骨的力学性能（包括强度和抗骨折性）的影响。骨头是由胶原蛋白和其他蛋白质、纳米级矿物质和水组成的，所有这些都是按等级自组装的。骨因其复杂的层次结构而具有优异的性能；它结实、坚硬、坚韧、重量轻。然而，促成这些优越性能的因素仍然没有得到很好的理解。这项基础和跨学科的研究将包括最先进的实验和多尺度建模，并将重点放在猪的骨骼发育（0-48个月），它的结构和成分随着年龄的增长而发生显著变化。这项研究的结果将有助于更好地预测人类骨质量，这仍然是一个突出的临床问题，并将指导设计具有优越机械性能的新型合成复合材料，用于生物医学，交通和能源领域。来自不同背景的学生将参与这项前沿研究。将开发新的课程，并向技术和非专业观众提供短期课程和其他介绍。技术摘要：骨是一种由胶原蛋白和其他蛋白质、羟基磷灰石矿物和水组成的生物纳米复合材料。这种复杂的结构赋予了骨骼优越的特性（坚固、坚硬、坚韧和重量轻）。然而，其影响因素仍未被很好地理解。在这个合作项目中，研究人员将测试两种假设：1)骨骼是一种由有机相和矿物相相互渗透而成的复合材料；2)与具有分散增强相的复合材料相比，具有互穿相的合成仿生复合材料将具有优越的力学性能。更具体地说，这些研究人员将通过多尺度实验和建模来确定互穿模型是否适用于不同矿化程度和不同微观结构的骨。开发猪骨（0-48个月大），展示一系列微观结构和矿物质含量将作为该项目的一部分进行研究。在胶原蛋白/矿物质水平上的应变作为施加应力的函数，使用高能x射线衍射在小角度和广角，将与理论所得的结果进行比较。此外，将设计和测试具有互穿相的合成生物激发材料，并将其性能与具有分散增强的复合材料进行比较。该项目有望提供对骨骼层次结构的基本理解，这将有助于更好地预测骨骼质量，并将指导设计用于不同应用的新型生物合成复合材料。来自不同背景的学生有望参与这项前沿研究，包括来自第五修正案西班牙裔高中的学生。将开发新的课程，并向技术和非专业听众作介绍。

Non-Technical Abstract: This collaborative project award by the Biomaterials program in the Division of Materials Research to University of Illinois Urbana-Champion and University of California San Diego is to investigate a new model of bone as a material that the two phases in bone, proteins and minerals, are interpenetrating (continuous), and to explore what implications this hypothesis has on bone's mechanical properties, including strength and resistance to fracture. Bone is made of collagen and other proteins, nano-sized minerals and water, all hierarchically self-assembled. Bone has excellent properties due to its complex hierarchical structure; it is strong, stiff, tough and light weight. However, factors contributing to these superior properties are still not well understood. This fundamental and interdisciplinary study will include state-of-the art experiments and multiscale modeling, and will focus on porcine developing bone (0-48 months) which exhibits significant changes in its structure and composition with age. Results from this research will lead to better predictions of bone quality in humans, which is still an outstanding clinical issue, and will guide in the design of novel synthetic composite materials with superior mechanical properties for applications in biomedical, transportation and energy fields. Students from diverse backgrounds will participate in this cutting-edge research. New courses will be developed and short courses and other presentations will be given to technical and lay audiences. Technical Abstract: Bone is a biological nanocomposite material made of collagen and other proteins, hydroxyapatite minerals and water, all hierarchically assembled. This complex structure gives bone its superior properties (strong, stiff, tough and light weight). However, the contributing factors are still not well understood. In this collaborative project, researchers will test two hypotheses: 1) bone is a composite material made of interpenetrating organic and mineral phases; and 2) synthetic bioinspired composites with interpenetrating phases will have superior mechanical properties, compared to composites with a dispersed reinforcing phase. More specifically, these investigators will determine if the interpenetrating model is valid for bone with varying degrees of mineralization and different microstructures via multiscale experiments and modeling. Developing porcine bone (0-48 months old), which exhibits a range of microstructures and mineral contents will be studied as part of this project. Strains at the collagen/mineral level as a function of applied stress, using high energy x-rays diffracting at small- and wide-angles, will be compared with those obtained theoretically. In addition, synthetic bioinspired materials with interpenetrating phases will be designed and tested, and compared their properties to those of composites with a dispersed reinforcement. This project is expected to provide fundamental understanding of bone's hierarchical structure, which will lead to better predictions of bone quality and will guide the design of new bioinspired synthetic composites for different applications. Students from diverse backgrounds are expected to participate in this cutting-edge research, including the students from Title V Hispanic-serving high schools. New courses will be developed, and presentations will be given to technical and lay audiences.