ISS: Thermophoresis in quiescent non-Newtonian fluids for bioseparations

ISS：静态非牛顿流体中的热泳用于生物分离

• 批准号: 2126481
• 负责人: James Gilchrist
• 金额: $ 40万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126481&HistoricalAwards=false
• 关键词: ISS; Thermophoresis; quiescent; non; Newtonian

There are many natural and industrial processes where nanoscale particles suspended in a fluid move as a result of a temperature gradient. These particles generally move from hot to cold regions. This phenomenon, which is known as thermophoresis, affects a wide variety of processes, such as drug delivery and bioseparations utilized for detecting viruses. However, the current understanding of thermophoresis is limited. Experimental studies have conflicting evidence, making it difficult to determine the fundamental mechanisms that drive particle motion. Very few studies have considered the motion of these particles in more complex fluids and gels. The challenge in interpreting experimental data is that it is difficult to separate effects of thermophoresis from effects of fluid flow arising from variations in the fluid density owing to variations in temperature. To overcome this limitation, this NSF-CASIS project will pair terrestrial experiments with those in microgravity onboard the International Space Station (ISS) where buoyancy-driven fluid flow is negligible. The goals are to determine the fundamental physics and chemistry driving thermophoresis in simple and complex fluids and to use this information for enhancing viral separation platforms by optimizing fluid properties. In an era when disease control affects everyone, this project will focus on developing enhanced and robust microfluidic viral-load detection devices.The objective of this project is to measure the thermophoretic motion of particles in complex fluids on the ISS to aid in the design of next-generation bioseparations devices for label-free viral load detection. Gravity-driven buoyancy-induced recirculation due to thermal expansion of the fluid is inhibited in microgravity, which will enable unambiguous measurements of thermophoresis. The project will use multiple particle tracking microrheology (MPT) to simultaneously obtain local thermophoretic and rheological data. Fluids will range from variable ionic strength Newtonian liquids to non-Newtonian fluids with varying degrees of linear viscoelasticity or a temperature dependent sol-gel transition. The size and surface properties of probe particles will be changed and will span properties of biologically relevant nanoparticles, such as viruses. Terrestrial experiments will focus on fluid property selection through rheological testing, particle synthesis, and downstream redesign of microfluidic platforms utilizing complex fluids to enhance bioseparations. The team will design these experiments with Tec Masters, Inc. to create a module that remotely performs all operations of sample manipulation, precision heating, high-speed/high-magnification imaging, and data transfer on the ISS. This basic research and first demonstration of the utility of microrheology in space will impact the rheology, colloid and interfacial science, and bioseparation communities and train postdoctoral, graduate and undergraduate researchers. The promise for enhancing life on Earth through these fundamental and applied experiments will be incorporated into outreach activities for K-12 students and underrepresented student populations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在许多天然和工业过程中，由于温度梯度，纳米级颗粒悬浮在流体运动中。这些颗粒通常从热区域移动到冷区域。 这种现象被称为嗜热，会影响多种过程，例如用于检测病毒的药物输送和生物序列。 但是，当前对嗜热的理解是有限的。 实验研究的证据相互矛盾，因此难以确定驱动颗粒运动的基本机制。 很少有研究认为这些颗粒在更复杂的液体和凝胶中的运动。解释实验数据的挑战在于，由于温度变化，很难将嗜热的影响与流体密度变化产生的流体流动的影响分开。为了克服这一限制，这个NSF-CASIS项目将将陆地实验与载浮力驱动的流体流动的国际空间站（ISS）的微重力实验相结合。 目标是确定基本的物理和化学在简单和复杂的流体中驱动嗜热疗法，并使用此信息通过优化流体特性来增强病毒分离平台。在一个疾病控制影响每个人的时代，该项目将集中于开发增强且健壮的微流体病毒载荷检测设备。该项目的目的是测量ISS上复杂流体中颗粒的嗜热运动，以帮助设计下一代生物散射设备，以实现无标签的无标签病毒载荷检测。由于流体的热膨胀而导致重力驱动的浮力诱导的再循环，这将在微重力中抑制，这将实现嗜热的明确测量。该项目将使用多个粒子跟踪微流变学（MPT）同时获得局部嗜热和流变数据。流体的范围从可变的离子强度牛顿液体到不同程度的线性粘弹性或温度依赖性的溶胶 - 溶胶 - 溶胶 - 凝胶过渡的非牛顿流体。探针颗粒的大小和表面特性将被更改，并将跨越生物学相关的纳米颗粒的性质，例如病毒。 陆地实验将通过流动性测试，颗粒合成以及利用复杂流体来增强生物序列化的微流体平台的下游重新设计来重点选择流体性能。 该团队将通过TEC Masters，Inc。设计这些实验，以创建一个模块，该模块可以远程执行样品操作，精密加热，高速/高磁化成像和ISS上的数据传输的所有操作。 这项基础研究和对空间中微笑学效用的首次证明将影响流变学，胶体和界面科学以及生物序列化社区，并培训博士后研究人员，研究生和本科研究人员。通过这些基本和应用实验来改善地球生活的承诺将纳入K-12学生的外展活动和代表性不足的学生人群中。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准通过评估来获得支持的。