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: 2323499
• 负责人: Arun Nair
• 金额: $ 25.49万
• 依托单位: University of Arkansas
• 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=2323499&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（例如由钴和铬降解的髋关节植入物）时，它们可以将这些重金属的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。更具体地说，它们可以进入由称为磷灰石的矿物组成的骨骼的困难部分。这些原子进入磷灰石的运动可以改变骨骼的工作方式，从而使它们更有可能破裂。但是，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去哪里以及它们如何影响骨骼强度。因此，该项目的目的是使用计算机建模和实验的组合，使用非常强大的X射线来弄清金属原子在磷灰石矿物中的位置，并确定它们是否使骨头更可损坏。通过结合计算机模型和实验，将开发技术，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含钴和铬含量的骨植入物的人的骨强度。与这项研究相结合，首席研究人员将努力创造环境，使学生对自己的科学能力更有信心。这将通过为学生提供在实验室工作的机会，通过教授吸引广泛观众的包容性课程的机会来完成，并充当经常不喜欢像他们（妇女和种族少数群体）科学角色的学生的榜样。技术摘要：钴（CO）和含植入物的铬（CO）降解与重金属离子的释放和骨断裂风险的增加有关。由于骨头主要由磷灰石矿物组成，该矿物具有很高的阳离子取代倾向，因此骨基质很可能正在吸收这些离子，从而导致晶体结构和力学的显着变化。主要研究人员假设将钴（CO）和铬（CR）掺入近种植体骨骼中在促进骨折中起着重要作用。但是，由于难以研究纳米尺寸的磷灰石，相对于此过程，还有几个未解决的问题，包括如何将CO和CR替换为磷灰石，离子如何影响磷灰石机械性能以及需要哪些CO和CR浓度来影响骨折。为了回答这些问题，将开发基于AB的磷灰石晶体模型，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来验证。这些数据将被合并以创建磷灰石晶体的多尺度模型，以研究由于CO和CR取代而引起的断裂起始过程。这项研究的结果可以通过创建一种新的治疗开发途径来最大程度地减少这种已经处于危险的人群中的骨折，从而使数百万具有钴铬植入物的北美人受益。此外，它们将促进磷灰石生物材料的可调节性，以实现未来的骨移植和脚手架应用。与研究结合在一起的是一项教育计划，旨在提高各种学生的科学领域的自我效能。这将通过为本科和研究生提供实验室的访问，开发具有文化相关的包容性科学课程，并充当代表性不足的学生的榜样来实现。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力和更广泛影响的评估来通过评估来获得支持的。