Multiscale structural and functional biomechanics of contracting platelet-fibrin based biomaterials and blood clots in oral microenvironment

项目摘要 富含血小板的血浆凝块是一种独特的生物材料，用于口腔和牙科外科手术 促进口腔伤口愈合和组织再生。而血小板的生化方面 以前已经研究过再生潜力，血小板的生物力学功能导致 口腔环境中损伤部位的纤维蛋白基质和血块的收缩尚未得到解决。血样 凝块收缩是激活的血小板和聚合纤维蛋白之间生物力学相互作用的结果， 口腔损伤部位止血凝块的两个主要成分是红细胞和较少的白细胞。 体内血栓收缩的生物医学重要性从促进牙齿和周围伤口的愈合明显可见。 通过接近伤口边缘并形成不透水的物理屏障来植入 口腔创伤中的细菌入侵和毒素传播。尽管血小板收缩功能很重要 用于口腔损伤部位的血液凝块和含有富含血小板的纤维蛋白外科止血剂的血栓的重塑 密封剂，血栓收缩动力学与激活的代谢和结构变化的关系 口腔创伤中的血小板在很大程度上仍不清楚。因此，拟议研究的主要目标是 发现血小板诱导血栓的多尺度和时间依赖的生物力学和结构机制 口腔微环境的收缩及其功能后果，包括对凝块的调节 机械性能和稳定性。重点抓好以下几个方面的工作：一、确定结构 从细胞和亚细胞水平研究了血小板诱导血栓收缩的机制。目标2.定义 唾液细胞外小泡对富含血小板收缩的结构特性和粘弹性的影响 血浆凝块。目的3.确定血小板激活的晚期结构、代谢和功能后果 以及口腔微环境的收缩。为了达到我们的目标，我们将应用最先进的生物物理和 来自分子和细胞的定量表征和结构细节的生化方法 水平达到整个血块的大小。通过应用不同技术的组合，包括高 分辨率光学显微镜、流变仪和生化分析，我们的项目将弥合不同 空间尺度，并将在分子、单细胞和单纤维水平之间建立联系，以 整个血液凝块的结构和机械调节。拟议的研究将建立一种机械性的 在存在唾液细胞外小泡的情况下，血小板驱动的凝块收缩的基础，这将产生见解 研究激活的血小板的结构和功能以及粘弹性能和 口腔损伤部位血小板-纤维蛋白支架的构筑。所获得的知识将提高我们的理解 了解口腔微环境中的止血情况，为新治疗方法的设计提供信息，并协助开发 以血小板-纤维蛋白为基础的口腔生物材料具有可调节的机械性能以改善患者 康复和口腔健康。

Project Summary Platelet-rich plasma clots are a unique biomaterial used for oral and dental surgical procedures to promote wound healing and tissue regeneration in the oral cavity. While aspects of platelet biochemical regenerative potential have been previously studied, the biomechanical function of platelets resulting in contraction of fibrin matrix and blood clots at injury sites in the oral environment has not been addressed. Blood clot contraction is a result of the biomechanical interactions between activated platelets and polymerized fibrin, the two major components of hemostatic clots at oral injury sites, other than red blood cells and fewer leukocytes. The biomedical importance of clot contraction in vivo is evident from promoting wound healing around teeth and implants by approximating the edges of the wound and formation of impermeable physical barriers against bacterial invasion and toxin propagation in oral wounds. Despite the importance of the platelet contractile function for remodeling of blood clots at oral injury sites and clots comprising platelet-rich fibrin surgical hemostatic sealants, the relation between clot contraction dynamics and metabolic and structural changes in activated platelets in oral wounds remains largely unknown. Thus, the main objective of the proposed research is to discover multiscale and time-dependent biomechanical and structural mechanisms of platelet-induced clot contraction in the oral microenvironment and its functional consequences, including modulations of clot mechanical properties and stability. We will focus on the following Aims: Aim 1. Determine structural mechanisms of platelet-induced clot contraction studied at the cellular and subcellular levels. Aim 2. Define the impact of salivary extracellular vesicles on structural properties and viscoelasticity of contracting platelet-rich plasma clots. Aim 3. Identify late-stage structural, metabolic, and functional consequences of platelet activation and contraction in the oral microenvironment. To reach our goals, we will apply state-of-the-art biophysical and biochemical methods with quantitative characterization and structural details from the molecular and cellular levels up to the scale of the entire clot. By applying a combination of different techniques, including high- resolution light microscopy, rheometry, and biochemical assays, our project will bridge the gap between different spatial scales and will establish relations between the molecular, single-cell and single-fiber levels to global structural and mechanical modulations of the entire blood clot. The proposed study will establish a mechanistic basis for platelet-driven clot contraction in the presence of salivary extracellular vesicles, which will yield insights into the structure and function of activated platelets as well as variations of viscoelastic properties and architecture of platelet-fibrin scaffolds at oral injury sites. The acquired knowledge will improve our understanding of hemostasis in the oral microenvironment, inform design of new treatment modalities and assist in development of platelet-fibrin-based biomaterials for oral cavities with modulated mechanical properties to improve patient recovery and oral health.