EAGER: Propulsion of enzyme-coated Janus particles through complex environments

这个项目的目标是合成一种微米大小的、能够自我推进的粒子，并表征这种粒子在复杂流体中的运动。球形颗粒表面的一部分被一种酶包裹，这种酶与周围液体中的过氧化物发生反应。粒子表面的反应产生了渗透压差，使粒子移动。酶促反应可以在周围介质中以非常低的过氧化物浓度推动颗粒，这使得自推进颗粒成为对过氧化物浓度敏感的生物系统的候选者。将测量一系列粘性流体的粒子速度，包括作为生物介质模型的复杂流体。在多相流体系统和生物组织等复杂环境中，自行式粒子是一种很有前途的运输工具，可以增强分子货物的运输和输送。研究人员将让本科生和高中生参与该项目，并将研究结果用于他们所在机构的外展项目。该项目包括实验和理论研究，以量化和阐明非牛顿环境中胶体粒子自驱动运动的机制。实验将利用一类Janus粒子，这些粒子通过在其部分表面涂上一层酶来推动自己。运动是由过氧化氢燃料在颗粒表面的溶液中的反应引起的，在颗粒周围产生不均匀的溶质分布，从而通过一种称为自扩散泳动的机制产生推进力。该项目将测试当前牛顿流体中自扩散电泳理论的预测，特别是粒子速度对流体粘度的依赖，然后研究更复杂的非牛顿流体中的运动，这些流体在推进粒子的尺寸尺度上是均匀的。这将使用聚合物溶液来完成，其中聚合物的旋转半径明显小于电机。研究结果将为复杂多相流体中自推进粒子的设计和应用奠定基础。

CBET - 1544617PI: Underhill, PatrickThe goals of this project are to synthesize a micron-sized particle that is capable of self-propulsion and to characterize the motion of the particle in complex fluids. A portion of the surface of the spherical particle is coated with an enzyme that reacts with peroxide in the surrounding fluid. The reaction at the particle surface creates an osmotic pressure difference across the particle, which causes it to move. The enzymatic reaction can propel the particle at very low peroxide concentrations in the surrounding media, which makes the self-propelled particle a candidate for use in biological systems that are sensitive to peroxide concentration. The velocity of the particle will be measured for a series of viscous fluids, including complex fluids that are models of biological media. Self-propelled particles are promising vehicles to enhance transport and deliver molecular cargoes in complex environments ranging from multiphase fluid systems to biological tissues. The researchers will involve undergraduate and high school students in the project and use results of the research in outreach programs at their institution.The project comprises experimental and theoretical studies to quantify and elucidate mechanisms for the self-driven motion of colloidal particles through non-Newtonian environments. The experiments will utilize a class of Janus particles that propel themselves using an enzyme coated on part of their surface. Motion results from the reaction of a peroxide fuel in solution on the particle surface producing a non-uniform distribution of solutes around the particle, which leads to propulsion by a mechanism called self-diffusiophoresis. The project will test predictions of current theories of self-diffusiophoresis in Newtonian fluids, especially the dependence of particle velocity on fluid viscosity, and then examine motion in more complex, non-Newtonian fluids that are homogeneous on the size scale of the propelling particle. This will be done using polymer solutions in which the polymer radius of gyration is significantly smaller than the motor. Results will form a foundation for self-propelled particle design and use in complex and multiphase fluids.