Abstract

Microfluidic devices and systems have demonstrated wide applicability in sample processing and analysis. The ability to integrate sample processing and analysis into a single platform is a key benefit of microfluidic technologies. This dissertation describes the design and fabrication two types of microfluidic devices developed to enhance membrane-based biosensors. First is a device for collecting particles into a highly confined region, locally enhancing their concentration. Second is a device for size-based particle separation capable of separating differently sized particles into separate streams. Both types of devices are fabricated with a thin top layer, providing a platform for synthetic membrane-based technologies. A particularly relevant example is that of solid-state nanopores, a type of membrane-based sensor that can be used for rapid and precise virus sensing. The particle trapping system uses a physical mechanism to immobilize and concentrate particles. It relies on filter-like nanofluidic channels incorporated into the design, which trap particles but allow the suspension medium to continue to flow through the system. Results show that tens to hundreds of particles can be collected in the trapping region in a matter of minutes from a dilute sample, enhancing the local concentration in the trap by a factor of about 105. The design allows for reliable trapping of 100% of analyte particles using a passive mechanism. The particle separation system relies on deterministic lateral displacement (DLD) for size-based discrimination. Like the chosen particle trapping system, DLD is passive, relying only on laminar flow characteristics to produce separation. Results from the design and fabrication show that DLD devices fabricated with a thin top layer can discriminate between 1 μm and 2 μm particles, separating them into distinct streams. The fabrication process produces unusual topology, introducing new variables into DLD functionality. Future work for this project includes overcoming residual issues with the designs, including clogging in the particle trapping devices and particle adhesion in the DLD devices. After these problems have been addressed, further work would include integrating the particle sorting and trapping designs into a single device, allowing for simultaneous processing and analysis of samples on a single chip.

Degree

PhD

College and Department

Ira A. Fulton College of Engineering; Electrical and Computer Engineering

Rights

https://lib.byu.edu/about/copyright/