| Separation by size is a fundamental analytical and preparative technique in biology, medicine, and chemistry. Deterministic lateral displacement (DLD) arrays are microfluidic devices capable of high-precision particle sorting based on size. In this thesis, we will discuss improvements in the functionality of DLD arrays and several new applications. We'll first discuss a methodology for performing sequential on-chip chemical treatment by using the DLD array to direct particles in the "bumping" trajectory across co-flowing reagent streams and demonstrates this technique with platelet labeling and washing and E. Coli lysis and chromosomal separation. We then discuss a deterministic microfluidic ratchet that could separate particles in an intermediate size range using a DLD array with triangular posts in an oscillating flow. We then extended this idea of using triangular posts in DLD arrays to continuous-flow operation and showed significant performance enhancements over arrays with circular posts when the triangle vertex is used as the displacement edge. Taking this idea of increasing device throughput to the next step, we developed a highly parallelized DLD array architecture for processing macroscopic fluid volumes by operating many arrays in parallel and showed flow rates on the order of 10 mL/min with a single-layer device and applied these high throughput DLD arrays to isolating viable circulating tumor cells from blood and dewatering algae for biofuel production. |
