Collaborative Research: Acoustic Tweezing Rheometry of Biological Fluids

该奖项由化学、生物工程、环境和运输系统部（CBET，工程局）的微粒和多相过程（PMP）项目授予，由生物基础设施部（BIO局）的生物研究仪器开发（IDBR）项目共同资助。测量生物材料和其他复杂流体（如聚合物液体）的物理和机械性能对科学家和工程师提出了特殊的挑战。这些材料的性质会由于材料与固体壁（如盛装材料的容器壁）之间的接触而改变。该合作项目涉及开发一种新设备和新方法来测量流体或固体的流变特性，以避免样品与固体壁之间的接触。这种方法被称为声镊子流变法，它利用声悬浮来保持小样本自由悬浮在空气或水中，同时对材料施加一个力，使其变形。然后，该设备通过记录样品形状随时间的变化来读取材料的响应。通过将样品的形状与作为项目一部分的计算机模拟进行比较，可以推断出材料的流变特性。这种新仪器将在各种科学和工程学科中得到应用。声学镊子流变仪将用于测量活性聚合物、生物流体和软组织的特性，而不会由于与固体壁接触而产生污染、生物活化或凝胶等人为影响。通过分析研究和计算模拟，建立了非接触测量材料常数的模型。声学镊子技术将用于粘弹性流体材料特性的测量。该方法将应用于生物体液和软组织，包括凝血过程中的全血和胶原蛋白凝胶。结果将广泛传播，包括向可能受益于新方法的生物群落推广。

CBET 1438569/1438567This award by the Particulate and Multiphase Processes (PMP) program in the Division of Chemical, Bioengineering, Environmental, and Transport Systems (CBET, Engineering Directorate), is co-funded by the Instrument Development for Biological Research (IDBR) program in the Division of Biological Infrastructure (BIO Directorate).Measuring the physical and mechanical properties of biological materials and other complex fluids such as polymeric liquids poses special challenges for scientists and engineers. The properties of these materials can change owing to the contact between the material and solid walls, such as the walls of a container holding the material. This collaborative project involves the development of a new device and new method to measure the rheological properties of fluids or solids that avoid contact between the sample and solid walls. The method is called acoustic tweezing rheometry, and it uses acoustic levitation to hold a small sample freely suspended in air or water while applying a force on the material that causes it to deform. The device then reads the response of the material by recording changes in the shape of the sample as a function of time. By comparing the shape of the sample with computer simulations carried out as part of the project, the rheological properties of the material can be deduced. This new instrument will find applications in a diverse array of science and engineering disciplines.Acoustic tweezing rheometry will be used to measure properties of active polymeric and biological fluids and soft tissue without artifacts such as contamination, biological activation or gelation due to contact with solid walls. A model will be developed for noncontact measurement of material constants through analytical studies and computational simulation. The acoustic tweezing technique will be developed and validated for measurement of material properties of viscoelastic fluids. The method will be applied to biological fluids and soft tissue, including whole blood during coagulation and collagen gel. Results will be disseminated broadly, including outreach to the biological communities that could benefit from the new method.