PFI-TT: Total Intervertebral Disc Replacement Device using Novel Energy Absorbing Materials.

该PFI项目更广泛的影响/商业潜力是开发一种原型器械，旨在改善全椎间盘置换（TDR）手术的当前护理标准。每年约有50万美元的美国人将接受涉及椎间盘置换的手术，导致器械市场超过10亿美元。这些手术通常是椎间融合术或TDR，并发症发生率较高。 大约三分之一的患者最终需要进行随访。 尽管根本原因尚不清楚，但最常使用的生物医学器械明显比原始椎间盘更硬，并且在整个椎间盘间隙中没有发生缓冲或力耗散;这可能是并发症（如下沉和相邻节段疾病）的重要因素。该研究将是首次对新型液晶弹性体（LCE）在脊柱器械中的潜在用途进行循环载荷研究。如果成功，拟议的研究将开发具有分层结构的稳定长期机械耗散特性的LCE，以模仿椎间盘的自然组织。涉及使用这种超耗散材料的其他潜在应用是用于体育或军事中使用的保护设备，例如头盔，以更好地防止脑震荡。该拟议项目将研究主链LCE，相对于硅树脂或水凝胶等传统橡胶类材料，这种材料具有极其优越的上级耗能性能。在机械应力下的液晶介晶重取向提供了用于耗散能量的温度和频率不敏感的机制，比典型的粘弹性更鲁棒。这项研究将是第一次调查主链LCE的循环力学性能。拟议的研究将产生一种LCE概念验证装置，该装置表现出在生物软组织中观察到的机械性能（即，各向异性、阻尼和低模量）。LCE将被合成为空间定制的装置，以匹配天然椎间盘的机械性能和结构。这些材料中独特的液晶结构使得循环行为难以先验估计，因此必须研究作为材料结构、应变率和位移大小的函数的直接表征。将研究LCE的高循环加载。通过该分析获得的基础知识将显示LCE用于TDR的可行性，并展示LCE用于阻尼应用的广泛适用性。该项目直接建立在NSF支持的基础研究发现之上。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this PFI project is to develop a prototype device aimed at improving the current standard of care for total disc replacement (TDR) procedures. Each year approximately $500,000 Americans will undergo surgery involving intervertebral disc replacement, resulting in a device market well over $1 billion. These procedures, which are most often interbody fusions or TDRs, are associated with a high rate of complications. Approximately one-third of patients will ultimately require a follow-up procedure. Although the underlying causes are unclear, the biomedical devices most often used are significantly stiffer than the original intervertebral disc, and no cushioning or force dissipation occurs across the disc space; this is likely a significant factor for complications such as subsidence and adjacent level disease. This study will be the first cyclic loading investigation into the use of novel liquid crystalline elastomers (LCEs) for potential use in spinal devices. If successful, the proposed research will develop LCEs for stable long-term mechanical dissipative properties with a hierarchical structure to mimic the natural organization of the intervertebral disc. Other potential applications involving the use this ultra-dissipative material are for protective equipment used in sports or military, such as helmets to better prevent concussions. The proposed project will investigate main-chain LCEs, which have vastly superior energy dissipation properties relative to traditional rubber-like materials such as silicone or hydrogels. Liquid crystal mesogen reorientation under mechanical stress provides a temperature and frequency insensitive mechanism for dissipating energy, more robust than typical viscoelasticity. This proposed research will be the first to investigate cyclic mechanical properties of main-chain LCEs. The proposed research will result in an LCE proof-of-concept device that exhibits mechanical properties seen in biological soft tissues (i.e., anisotropy, dampening, and low modulus). The LCE will be synthesized a spatially tailored device to match the mechanical properties and structure of a natural disc. The unique liquid-crystal structure within these materials makes cyclic behavior difficult to estimate a priori, and therefore direct characterization as a function of material structure, strain rate, and displacement magnitude must be investigated. High-cycle loading of LCEs will be investigated. Fundamental knowledge gained through this analysis will show the feasibility of LCEs for TDR and demonstrate broad applicability of LCEs for dampening applications. This project builds directly from fundamental research discovery supported by the NSF.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.