Microfluidics and Chip Development

During the course of the summer, I had the privilege to work with Dr. Carlos Escobedo and his team of researchers on the topics of microfluidics and Lab-On-Chip (LOC) technology. Microfluidics is a branch of fluid dynamics which utilizes small volumes of fluid to perform tests under ideal conditions, and LOC is the process of using microfluidics for experiments in small-scale environments. I participated in two LOC projects, the first for bacterial analysis and the second for microplastic separation. The goal of the first project was to observe if Vibrio Cholerae bacteria was attracted to a variety of chemo attractants. To observe this interaction under microfluidic conditions, we developed a chip which when flooded with chemoattractant trapped a portion in the chip. We could then remove the non-entrapped chemoattractant from the sides and refill the chip with bacteria. Observations of the bacteria’s movement were then taken using a microscope attached to a digital camera. The second project focused on microplastics, which are plastic particulates under 5mm in diameter, our smallest sample being 10μm. Due to their size standard filtering techniques were ineffective at separating them, which led to us using Deterministic Lateral Displacement (DLD). DLD utilizes an array of pillars to create spots of changing pressure for passing particles. The array is designed so larger particles are unaffected while smaller particulates will be redirected and collected separately. To arrange the plastics into their types, a centrifugal design was used. This design functions similarly to a centrifuge, which by rapidly spinning a substance separates out materials based on density. The chip works under a similar theory, but instead uses a spiral channel to force the particles in a repeated circular spinning motion. The particles then exit with differing directionalities based on where they were in the channel, allowing for collection.