Microhemorheology

微血液流变学

• 批准号: RGPIN-2020-07020
• 负责人: Fenech, Marianne
• 金额: $ 2.33万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760105
• 关键词: Microhemorheology

The long-term goal of this research program is to fulfill a role in the international efforts to develop a precise model of microscopic blood flow. It is essential to describe blood flow in both physiological and diagnostic settings. Blood is a very interesting fluid that must be better understood to serve many medical applications: understanding physiology, pathology as well as understanding how blood flows in medical devices. The blood at the microscale cannot be considered as liquid flow, but rather as a collection of particles: the red blood cells (RBCs). The RBCs represents approximately half of the volume of the blood and the rest of the volume of the blood is occupied by plasma. Blood is in the family of suspensions particularly complex: it is a dense suspension of particles that are highly deformable and interact with each other, for example, they can aggregate. We are interested in the rheology of blood because this is the foundation of its mechanics: it is the link between force and displacements. Great results are dating back to the 1970s that show that blood is a shear-thinning fluid i.e. its apparent viscosity decreases when shear rate increases. However, this overall description cannot predict the blood behavior at the microscale because in this circumstance the local viscosity depends on many other factors such as local shear, cell density or cells interaction with each other or with the walls. Besides this overall model cannot be used to understood or predict local transfers of gas, nutriment or drugs. It has been shown that the local density of red blood cells (or hematocrit) is inconstant in the flow, for example there are areas of the flow where there is almost no red blood cell including close to the walls and areas of high concentration especially in the center of the vessel or at the bifurcations. The interactions of the cells and the strong heterogeneities, although already observed in the '70s, have never been included in the rheological modeling of the blood. Recently, great progress has been made in the field of suspension rheology, which highlights the importance of the local particle density. Regarding blood, it is time to couple the rheological measurements with the characterization of local microstructures. Relying on world-class highly-specific equipment, along with original experimental procedures developed in our laboratory and benefiting of strong international collaborations, our goal is to study cellular transport in the microcirculation focusing on the characterization of blood flow in relation to microstructure. In particular, we aim to study the collective dynamics of red blood cells in confined flows and networks, for healthy and model of pathological cells.

该研究项目的长期目标是在国际上开发精确的微观血流模型的努力中发挥作用。描述生理和诊断环境中的血流至关重要。血液是一种非常有趣的流体，必须更好地理解它才能服务于许多医疗应用：了解生理学、病理学以及了解血液在医疗设备中的流动方式。微观尺度的血液不能被视为液体流动，而是颗粒的集合：红细胞（RBC）。红细胞大约占血液体积的一半，其余的血液体积被血浆占据。血液属于特别复杂的悬浮液家族：它是一种致密的颗粒悬浮液，这些颗粒高度可变形并且彼此相互作用，例如它们可以聚集。我们对血液流变学感兴趣，因为这是其力学的基础：它是力和位移之间的联系。伟大的结果可以追溯到 20 世纪 70 年代，这些结果表明血液是一种剪切稀化流体，即当剪切速率增加时，其表观粘度会降低。然而，这种总体描述无法预测微观尺度的血液行为，因为在这种情况下，局部粘度取决于许多其他因素，例如局部剪切、细胞密度或细胞彼此或与壁的相互作用。此外，这个整体模型不能用于理解或预测气体、营养物或药物的局部转移。已经表明，血流中红细胞的局部密度（或血细胞比容）是不稳定的，例如，在血流的某些区域中几乎没有红细胞，包括靠近壁的区域和高浓度区域，特别是在血管中心或分叉处。尽管在 70 年代就已经观察到细胞之间的相互作用和强烈的异质性，但从未将其纳入血液流变模型中。近年来，悬浮流变学领域取得了巨大进展，凸显了局部颗粒密度的重要性。对于血液，是时候将流变测量与局部微观结构的表征结合起来了。依靠世界一流的高特异性设备，以及我们实验室开发的原创实验程序，并受益于强有力的国际合作，我们的目标是研究微循环中的细胞运输，重点关注与微结构相关的血流特征。特别是，我们的目标是研究红细胞在有限流动和网络中的集体动力学，用于健康细胞和病理细胞模型。