Non-invasive optical biomarkers to quantify engineered bone tissue development

描述（由申请方提供）：骨组织再生是各种临床手术（包括骨折修复、重建手术和脊柱融合术）后恢复骨骼功能所必需的。组织工程骨与传统的骨移植物相比具有许多优点，可用于骨的修复和再生。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。本项目的目的是开发定量光学生物标志物，以识别和监测工程化骨组织在体外发育过程中的生物化学，微观结构和整体机械性能的变化。这项工作的重点是动态变化发生的三维丝支架与人类骨髓间充质干细胞的发展成为功能性骨组织。该建议的中心假设是，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法来非侵入性地测量，以确定发育组织的生化和微观结构特性。为了检验这一假设，将在目标1中鉴定来自不同细胞和细胞外基质组分的固有荧光和光散射信号，并将其与传统组织学和分子生物学技术相关联。目标1中确定的微观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下的总体机械功能。总的来说，这些目标将提供一个独特的理解，如何生化状态和机械功能的工程组织的变化，在成骨。通过仅使用识别光学对比度的内在来源的非侵入性技术，该研究的结果可用于优化未来工程化功能性骨组织的方法，并将能够在手术修复后将工程化结构并入天然组织时监测工程化结构。 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结构和功能，这将提高组织工程技术的效率，以开发功能性骨替代品。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，在不使用电离辐射的情况下，以比传统成像技术更高的分辨率评估再生。

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.