This project is funded by the Chemistry Division of the Mathematical and Physical Sciences Directorate. Professors Aaron Timperman from the University of Illinois and Boyd Edwards from Utah State University are investigating the fundamental mechanisms of a new separation method called microfluidic traveling-wave electrophoresis (TWE). TWE is a promising method for reducing the complexity of samples that may come from biological organisms or the environment. In the investigation of the mechanisms of TWE, the team is determining precisely how TWE works and on optimizing its performance. The unique characteristics of TWE separations make it well-suited for applications that cannot be achieved with other separation methods. The TWE separation is driven with very low voltages (+/-0.5 V) which are 1,000 to 10,000 times smaller than its nearest relative, microchannel electrophoresis. This low voltage requirement makes TWE highly compatible with fieldable sensing systems. TWE should prove helpful in applications such as detection of biomarkers in human medical, forensic, and drug testing, detection of toxic substances in the environment, and detection of threat agents for homeland defense. The team collaborates with the Illinois Academic Ambassadors to enhance exposure of middle school and high school students to STEM research.
A combined experimental and theoretical modeling approach is used to provide a thorough and quantitative description of the mechanisms of TWE. TWE is distinct as a low frequency AC electrophoretic separation in which a longitudinal electric field wave propagates through the microfluidic channel. The separation mechanisms of TWE are unique: TWE can rapidly switch between separative transport, non-separative transport, and immobilization simply by changing the frequency of the traveling wave; and both anions and cations move in the same direction. The goal of this work is to fully understand and quantitatively describe the fundamental mechanisms of traveling wave electrophoresis. The objectives are: 1) determining the mechanisms of zone migration, 2) determining the mechanisms of zone dispersion, and 3) defining the fundamental equations of separation efficiency, resolution, and peak capacity. The experimental results guide the development of the theoretical models, and the fundamental equations derived are experimentally verified. These fundamental equations provide a basis with which this separation method can be quantitatively compared with others and inform optimal device design. The experimental team includes both undergraduate and graduate students. This is an interdisciplinary project that exposes students to separations, theoretical modeling, and fabrication in Engineering. An outreach component is included that impacts middle and high school students, exposing them to STEM disciplines.
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.
