Non-invasive optical biomarkers to quantify engineered bone tissue development

描述（由申请人提供）：骨组织再生是在各种临床程序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。与传统骨移植相比，组织工程骨在修复和再生骨方面具有许多优点。然而，目前用于评估和优化工程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。本项目的目的是开发定量光学生物标志物，以识别和监测工程骨组织在体外发育过程中的生化、微观结构和整体力学性能的变化。这项工作的重点是发生的动态变化，三维丝支架与人间充质干细胞种子发育成功能的骨组织。该提案的中心假设是，内源性光信号可以使用多光子成像和深度分辨光散射光谱非侵入性测量，以确定发育组织的生化和微观结构特性。为了验证这一假设，将在Aim 1中识别来自不同细胞和细胞外基质成分的固有荧光和光散射信号，并与传统的组织学和分子生物学技术相关联。在Aim 1中鉴定的显微结构组织的光学生物标志物将在Aim 2中用于预测骨组织在拉伸和压缩中的整体力学功能。总的来说，这些目标将提供一个独特的理解如何在成骨过程中改变工程组织的生化状态和机械功能。通过仅使用非侵入性技术来识别光学对比的内在来源，本研究的结果可用于优化未来的工程功能骨组织方法，并将成为一种监测工程构建物在手术修复后融入原生组织的手段。

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.