Soft Matter and Complex Systems Seminar

Droplet microfluidics is an innovative technique in biomedical research that leverages the creation of small, isolated compartments formed by immiscible fluids, typically a water-in-oil system, within a network of microscale channels on a chip. In this talk, I will explore droplet formation in the very low capillary number regime. Interestingly, droplet formation in this regime diverges from the well-known squeezing mechanism, as evidenced by a significant increase in droplet size and neck length before pinch-off with respect to the capillary number. A generalized scaling law was developed to predict droplet volume in microfluidic cross-junctions and was validated using experimental data from devices with varying cross-sectional geometries. These findings deepen our understanding of droplet formation mechanics in the very low capillary number range. Additionally, I will discuss the practical applications of droplet microfluidics as micro-sized incubators for cell culture. Effective strategies for reducing the loading time of cell-containing media and minimizing droplet liquid mass transport through the permeable PDMS material will be presented, resulting in the ability to sustain the viability of most cells for over 24 hours.