Collaborative Research: Predicting the Mechanical Properties of Biomimetic Apatite Crystals Due to Co and Cr Ion Substitutions

合作研究：预测因 Co 和 Cr 离子取代而产生的仿生磷灰石晶体的机械性能

• 批准号: 2323500
• 负责人: Alix Deymier
• 金额: $ 32.24万
• 依托单位: University of Connecticut Health Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2323500&HistoricalAwards=false
• 关键词: Collaborative; Research; Predicting; Mechanical; Properties

Non-technical Abstract:When implants, like hip implants made of cobalt and chrome degrade, they can release atoms of those heavy metals into the surrounding bone. Some of those atoms can make their way into the bone itself; more specifically they can get inside the hard part of your bones which is made up of a mineral called apatite. The movement of these atoms into the apatite can change the way your bones work, making them more likely to break. However, because the apatite minerals in your bones are extremely small, it has been very difficult to study where these heavy metal ions go and how they affect bone strength. The goal of this project is therefore to use a combination of computer modelling and experiments using very powerful X-rays to figure out where the metal atoms go in the apatite mineral and determine whether or not they make the bone more breakable. By combining computer models and experiments, techniques will be developed that allow researchers to understand how metal atoms interact with bone apatite and predict how those atoms affect bone strength in the millions of people with cobalt and chromium containing bone implants. Integrated with this research, the principal investigators will strive to create environments that make students more confident about their scientific abilities. This will be done by providing opportunities for students to work in the lab, by teaching inclusive classes that reach broad audiences, and by acting as role models for students who do not often see people like them (women and racial minorities) in scientific roles. Technical Abstract:Degradation of cobalt (Co) and chromium (Cr) containing implants are associated with release of heavy metal ions and an increase in bone fracture risk. Since bone is primarily composed of apatite mineral which exhibits a high propensity for cationic substitutions, it is likely that the bone matrix is absorbing these ions resulting in significant changes in crystal structure and mechanics. The principal investigators hypothesize that the incorporation of cobalt (Co) and chromium (Cr) in the near-implant bone plays a significant role in promoting fracture. However, due to the difficulty in studying nano-sized apatites, there remain several unanswered questions relative to this process including how Co and Cr substitute into apatite, how the ions affect the apatite mechanical properties, and what Co and Cr concentrations are needed to affect bone fracture. To answer these questions, an ab initio-based model of apatite crystals with Co and Cr substitutions will be developed to predict the change in crystallographic and mechanical properties of apatite crystals at the nanoscale. These predictions will be validated by experimental approaches using biomimetic apatite systems and high-energy synchrotron X-ray diffraction techniques. These data will be combined to create multiscale models of apatite crystals to study fracture initiation processes due to Co and Cr substitutions. The results from this study can benefit millions of North Americans with cobalt-chrome implants by creating a new avenue for treatment developments to minimize fracture in this already at-risk population. In addition, they will facilitate the tunability of apatite biomaterials for future bone graft and scaffolding applications. Integrated with the research, is an educational plan which seeks to increase self-efficacy in the realm of science for a variety of students. This will be accomplished by providing lab access to undergraduate and graduate students, developing culturally relevant inclusive scientific courses, and acting as role models for under-represented students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：当植入物（例如由钴和铬制成的髋关节植入物）降解时，它们会将这些重金属原子释放到周围的骨骼中。其中一些原子可以进入骨骼本身；另一些则可以进入骨骼。更具体地说，它们可以进入骨骼的坚硬部分，该部分由一种叫做磷灰石的矿物质组成。这些原子移动到磷灰石中可以改变骨骼的工作方式，使它们更容易骨折。然而，由于骨骼中的磷灰石矿物质非常小，因此很难研究这些重金属离子的去向以及它们如何影响骨骼强度。因此，该项目的目标是结合计算机建模和使用非常强大的 X 射线的实验来找出金属原子在磷灰石矿物中的位置，并确定它们是否会使骨头更易碎。通过结合计算机模型和实验，将开发出一些技术，使研究人员能够了解金属原子如何与骨磷灰石相互作用，并预测这些原子如何影响数百万植入含钴和铬骨植入物的人的骨强度。结合这项研究，主要研究人员将努力创造让学生对自己的科学能力更加自信的环境。这将通过为学生提供在实验室工作的机会、教授覆盖广泛受众的包容性课程以及为那些不经常看到像他们这样的人（女性和少数族裔）担任科学角色的学生充当榜样来实现。技术摘要：含钴 (Co) 和铬 (Cr) 的植入物的降解与重金属离子的释放和骨折风险的增加有关。由于骨骼主要由磷灰石矿物质组成，磷灰石矿物质具有很强的阳离子取代倾向，因此骨基质很可能吸收这些离子，导致晶体结构和力学发生显着变化。主要研究人员假设，近种植体骨中钴 (Co) 和铬 (Cr) 的掺入在促进骨折方面发挥着重要作用。然而，由于研究纳米级磷灰石的难度，与此过程相关的几个未解决的问题仍然存在，包括Co和Cr如何替代磷灰石，离子如何影响磷灰石的机械性能，以及需要什么Co和Cr浓度来影响磷灰石的机械性能。骨折。为了回答这些问题，我们将开发 Co 和 Cr 取代的磷灰石晶体的从头计算模型，以预测纳米级磷灰石晶体的晶体学和机械性能的变化。这些预测将通过使用仿生磷灰石系统和高能同步加速器 X 射线衍射技术的实验方法得到验证。这些数据将结合起来创建磷灰石晶体的多尺度模型，以研究由于 Co 和 Cr 替代而引起的断裂萌生过程。这项研究的结果可以为数以百万计的接受钴铬合金植入物的北美人带来好处，为治疗开发开辟一条新途径，以最大限度地减少这一已经处于危险之中的人群的骨折风险。此外，它们还将促进磷灰石生物材料的可调性，以用于未来的骨移植和脚手架应用。与研究相结合的是一项教育计划，旨在提高各种学生在科学领域的自我效能。这将通过向本科生和研究生提供实验室访问权限、开发与文化相关的包容性科学课程以及为代表性不足的学生充当榜样来实现。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持。智力价值和更广泛的影响审查标准。