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

点击翻译按钮获取中文摘要

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.