CAREER: Electrohydrodynamic Coulter Counting

0846705 Chena Coulter计数器通过通过小孔的电流调制来检测和表征颗粒。这项研究希望建立一种使用电动流体动力(EHD)锥形射流进行库尔特计数的新范式，并展示该技术在量化和部署从生物大分子到合成纳米颗粒等纳米级物体方面的潜力。阻性纳米孔传感是使用生物或合成纳米孔的库尔特计数的微型化派生。当代的纳米孔传感器通常直径固定，要么寿命短，要么重复性差。这些限制可以通过利用EHD锥形-喷射过渡来绕过，这是一种独特的现象，允许从现成的更大的喷嘴中生产可调的纳米级液体喷射。为此，将结合实验和分析工具，以确定微米和亚微米级别的可重复使用的EHD喷注所需的条件。通过将库尔特计数与EHD锥形射流相结合，将开发出一种用于部署纳米物体的滴放技术，其单粒子精度将达到前所未有的水平。这项研究将解决与EHD库尔特计数技术发展相关的以下基本问题：是否可以重复产生和检测有或没有固有脉动的纳米级EHD射流？可以用液体喷射器代替人工合成的孔洞来完成库尔特计数吗？在EHD部署中能否实现单粒子精度？研究中概述的相关实验和分析研究将揭示支配纳米级EHD射流动力学和稳定性的标度律，并建立EHD库尔特计数新技术的性能边界。EHD库尔特计数器的成功开发将使我们能够在可调的长度范围内分析药物胶囊和量子点等纳米颗粒，而不需要诉诸标记，并能够以单分子精度部署大分子用于蛋白质纳米阵列和体外分隔。在这项研究的基础上，PI将开发一门新的研究生级别的微型物理化学流体力学课程，并将通过杜克大学的普拉特研究员和NSF REU项目培训本科生研究人员。PI将从南方工程学校招聘一名教师进行两个暑期实习，这是一所高中，提供工程预科课程，招生人数以非裔美国人为主。这位教师将参与建立EHD Coulter计数器的原型，并培训大学生在高中水平上交流科学思想，然后在PI的协助下，将最先进的微流体研究知识转移到支持北卡罗来纳州标准课程的高中水平课程单元中。

0846705 ChenA Coulter counter detects and characterizes particles by the modulation of electrical current through a small fluidic aperture. This study hopes to establish a new paradigm of Coulter counting using electrohydrodynamic (EHD) cone-jets, and demonstrate the potential of this technique in quantifying and deploying nanoscale objects ranging from biological macromolecules to synthetic nanoparticles. Resistive nanopore sensing is a miniaturized descendent of Coulter counting using biological or synthetic nanopores. Contemporary nanopore sensors typically have fixed diameters and suffer from either short life spans or low reproducibility. These limitations can be circumvented by exploiting the EHD cone-jet transition, a unique phenomenon that permits production of tunable nanoscale liquid jets from much larger nozzles off-the-shelf. To this end, experimental and analytical tools will be combined to identify conditions required for reproducible EHD jets at both micron and sub-micron levels. By integrating Coulter counting with EHD cone-jets, a drop-and-place technique for deploying nano-objects will be developed with unprecedented single-particle accuracy. This study will address the following fundamental questions associated with the development of the EHD Coulter counting technique: Can nanoscale EHD jets, with or without intrinsic pulsations, be reproducibly generated and detected? Can a liquid jet be used in lieu of a synthetic pore to accomplish Coulter counting? Can single-particle accuracy be achieved in EHD deployment? The interrelated experimental and analytical investigations outlined in the study will reveal scaling laws governing the dynamics and stability of nanoscale EHD jets, and establish the performance boundary of the new technique of EHD Coulter counting. The successful development of an EHD Coulter counter would enable the analysis of nanoparticles such as drug capsules and quantum dots over a tunable range of length scale without resorting to labeling, and the deployment of macromolecules with single-molecule accuracy for protein nanoarrays and in vitro compartmentalization. Based on this research, the PI will develop a new graduate-level course in Microscale Physicochemical Hydrodynamics and will train undergraduate researchers through the Pratt Fellows and NSF REU programs at Duke University. The PI will recruit a teacher for two summer internships from the Southern School of Engineering, a high school that offers a pre-engineering program with a predominant African American enrollment. This teacher will participate in building prototype EHD Coulter counters and in training university students to communicate scientific ideas at the high school level and then, assisted by the PI, transfer the knowledge in state-of-the-art microfluidics research into a high school level curricular unit that supports the North Carolina Standard Course of Study.