Non-invasive optical biomarkers to quantify engineered bone tissue development

描述(申请人提供)：骨组织再生是在各种临床手术后恢复骨骼功能所必需的，包括骨折修复、重建手术和脊柱融合。与用于骨修复和再生的传统骨移植相比，组织工程骨具有许多优点。然而，目前用于评估和优化工程化骨组织生长的方法缺乏空间和时间分辨率来表征组织发育过程中发生的动态细胞-基质相互作用。本项目的目标是开发定量的光学生物标志物，以识别和监测工程化骨组织在体外发育过程中生化、微观结构和整体力学性能的变化。这项工作主要关注种植了人骨髓间充质干细胞的三维丝质支架在发育成功能性骨组织过程中发生的动态变化。这一提议的中心假设是，可以使用多光子成像和深度分辨光散射光谱来非侵入性地测量内源性光学信号，以确定发育中组织的生化和微观结构特性。为了验证这一假设，来自不同细胞和细胞外基质成分的内在荧光和光散射信号将在目标1中被识别，并与传统的组织学和分子生物学技术相关联。目标1中确定的微结构组织的光学生物标志物将用于预测目标2中骨组织在拉伸和压缩时的整体机械功能。这些目标将提供对工程组织在成骨过程中的生化状态和机械功能如何变化的独特理解。通过只使用识别内在光学对比来源的非侵入性技术，这项拟议研究的结果可以用于优化未来工程化骨组织的方法，并将使一种手段，当工程构造在手术修复后被结合到天然组织中时，对其进行监测。 公共卫生相关性：拟议的研究将提供一套非侵入性光学技术来评估骨骼结构和功能，这将提高组织工程技术改进以开发功能性骨替代品的效率。对于数百万接受涉及骨修复的外科手术的患者来说，这项研究还将提供一种方法，以比不使用电离辐射的传统成像技术更高的分辨率来评估再生。

DESCRIPTION (provided by applicant): Bone tissue regeneration is necessary to restore skeletal function following a variety of clinical procedures, including bone fracture repair, reconstructive surgery, and spinal fusions. Tissue-engineered bone offers a number of advantages over traditional bone grafts used for the repair and regeneration of bone. However, the current methods employed to evaluate and optimize the growth of engineered bone tissue lack the spatial and temporal resolution to characterize the dynamic cell-matrix interactions that occur during tissue development. The objective of this project is to develop quantitative optical biomarkers to identify and monitor changes in the biochemical, microstructural, and overall mechanical properties of engineered bone tissue during its in vitro development. This work focuses on the dynamic changes that occur as three-dimensional silk scaffolds seeded with human mesenchymal stem cells develop into functional bone tissue. The central hypothesis of this proposal is that endogenous optical signals can be measured non-invasively using multi-photon imaging and depth-resolved light scattering spectroscopy to determine the biochemical and microstructural properties of the developing tissue. To test this hypothesis, the intrinsic fluorescence and light scattering signals from different cellular and extracellular matrix components will be identified in Aim 1 and correlated with traditional histological and molecular biology techniques. The optical biomarkers for microstructural organization identified in Aim 1 will be used to predict the overall mechanical function of the bone tissue in tension and compression in Aim 2. Collectively, these aims will provide a unique understanding of how the biochemical status and mechanical function of engineered tissue changes during osteogenesis. By using only non-invasive techniques that identify intrinsic sources of optical contrast, the outcomes of this proposed research can be used to optimize the future approaches to engineering functional bone tissue and will enable a means to monitor engineered constructs as they are incorporated into native tissue following surgical repair. PUBLIC HEALTH RELEVANCE: The proposed research will provide a set of non-invasive optical techniques to assess bone structure and function, which will improve the efficiency by which tissue engineering techniques are refined to develop functional bone substitutes. For the millions of patients that undergo surgical procedures that involve bone repair, this research will also provide a means to evaluate regeneration with greater resolution than traditional imaging techniques without the use of ionizing radiation.