Non-Equilibrium Ion and Fluid Transport in Microfluidic Ionic Circuits
Ion exchange membranes are critical components in electrodialysis (ED) and electrodeionization (EDI) processes. Under electric fields, the ion concentrations and local charge densities are dynamically modulated due to selective ion transport, resulting in a host of complex electrokinetic phenomena such as ion concentration polarization, extended space charges, and non-linear electro-osmotic flows and instabilities. We combine synthetic ion exchange membranes and microfluidics to create ionic transistors, and use circuit models to study these non-equilibrium ion and fluid transport behaviors. Our goals are (1) understanding membrane and interfacial properties using electrochemical circuit theories; (2) enabling selective separation of like-charge ions in ED & EDI; (3) creating biomimicking electrokinetic devices to enhance excitable tissue regeneration.
Selected publications
(1) Sun, G., Wan, J., Lu, H., “Rapid and Multi-cycle smFISH Enabled by Microfluidic Ion Concentration Polarization for In-situ Profiling of Tissue-specific Gene Expression in Whole C. elegans.” Biomicrofluidics, 13, 064101 (2019).
(2) Zhang, C., Sun, G., Senapati, S., Chang, H.-C., “A Bifurcated Continuous Field-Flow Fractionation (BCFFF) Chip for High-Yield and High-Throughput Nucleic Acid Extraction and Purification.” Lab on a Chip, 19, 3853-3861 (2019).
(3) Sun, G., Pan, Z., Senapati, S., Chang, H.-C., “Concentration-Gradient Stabilization with Segregated Counter-and Co-Ion Paths: A Quasistationary Depletion Front for Robust Molecular Isolation or Concentration.” Physical Review Applied, 7, 064024 (2017).
(4) Sun, G., Senapati, S., Chang, H.-C., “High-Flux Ionic Diodes, Ionic Transistors and Ionic Amplifiers Based on External Ion Concentration Polarization by An Ion Exchange Membrane: A New Scalable Ionic Circuit Platform.” Lab on a Chip, 16, 1171-1177 (2016). (Cover Article)
(5) Sun, G., Slouka, Z., Chang, H.-C., “Fluidic-Based Ion Memristors and Ionic Latches.” Small, 11, 5206-5213 (2015).