Development of non-contact rheometry for measuring rheological properties of biological fluids

摘要/总结 背景：生物体液的流变特性与多种生理学密切相关。 流程。例如，血液粘度紊乱与以下疾病的进展显着相关： 冠心病、外周动脉疾病、中风和高粘滞综合征。表面张力 粘液的产生受到肺部病理过程的影响。虽然流体的流变特性是 对于诊断和评估疾病进展至关重要的重要生物标志物，流变测定仪器具有 主要是为工业应用而开发的。现有的基于旋转和基于管的流变测量 设备无法同时测量流体的表面张力和粘度。此外，还有 当前用于测量粘度的流变仪和测量方法的各种缺点 表面张力，例如需要接触样品、需要高技能的操作员和清洁 每个样品之间的测试室。 该项目旨在通过开发非接触式流变测量来解决这些未满足的关键需求 使用小体积样品（稀薄样品）测量生物液体表面张力和粘度的方法 层流体）。 方法：我们将利用超声波作为激励源或“声压头”来产生传播 流体表面的毛细波并使用光学相干断层扫描 (OCT) 进行测量 精确记录波动的质点位移的装置。通过这种实验方法，样本 培养皿中的任何部分都不会直接接触测量设备的任何部分。我们之前的工作有 利用深层流体状态中的毛细波来测量表面张力和粘度。我们将以此为基础 先前的工作将理论模型扩展到薄层流体情况，即浅层流体中的毛细波 制度，以类似的非接触方式。我们将优化所提出的流变测量方法以实现 薄层测量的高精度测量。 为了实现该项目的目标，我们提出以下具体目标： • 目标 1) 构建并验证浅层流变特性的理论模型 流体情况。 • 目标 2) 优化流变采集方法和信号处理以产生稳健的结果 在薄薄的流体层中。 影响：所提出的技术将进行测量，具有以下优点，包括 非接触式、全自动、快速且无需在测试之间进行清洁，这提供了生物学友好的环境 环境。

ABSTRACT/SUMMARY Background: Rheological properties of biological fluids are closely linked with various physiological processes. For example, disorders of blood viscosity are significantly associated with the progression of coronary heart disease, peripheral artery diseases, stroke and hyperviscosity syndromes. The surface tension of mucus is influenced by pathological processes in the lungs. While rheological properties of fluids are important biomarkers critical to diagnose and evaluate progression of diseases, rheometry instruments have been primarily developed for industrial applications. Existing rotational-based and tube-based rheometry devices are not capable of measuring both surface tension and viscosity of fluids. Additionally, there are various drawbacks of current rheometry instruments for measuring viscosity and methods for measuring surface tension such as the need for contacting samples, necessitating highly skilled operators, and cleaning the testing chamber between each sample. This project aims to address these unmet and critical needs by developing a non-contact rheometry method for measuring biological fluid surface tension and viscosity using small volume samples (thin- layer fluid). Methods: We will utilize ultrasound as an excitation source or “acoustic indenter” to generate a propagating capillary wave on the surface of the fluid and use optical coherence tomography (OCT) as a measurement device to precisely record particle displacements of wave motion. With this experimental approach, the sample in a Petri dish is never in direct contact with any part of the measurement apparatus. Our previous work has utilized capillary waves in a deep fluid regime to measure surface tension and viscosity. We will build on this previous work to extend the theoretical model into the thin-layer fluid case, capillary waves in a shallow fluid regime, in a similar non-contact fashion. We will optimize the proposed rheometry method to achieve measurements with high accuracy and precision for thin-layer measurements. To accomplish the goals of this project we propose these Specific Aims: • Aim 1) Construct and validate the theoretical model for rheological properties in the shallow fluid case. • Aim 2) Optimize the rheometry acquisition method and signal processing to yield robust results in thin fluid layers. Impact: The proposed technique will carry out measurements with the following advantages including being non-contact, fully automated, fast, and not needing cleaning between tests, which provides a biology-friendly environment.