| The promise of increased portability and throughput in conjunction with reductions in cost, analyte consumption and handling, has propelled microfluidics to the forefront in a quest to obtain total micro-analysis systems superior in function to their lab-sized counterparts. This thesis addresses two critical processes key to lab-chip functionality, namely the creation of an efficient electrokinetic micro-mixer and conversely, the production of a stable concentration gradient generator. In the course of this study, a novel method of complex, microscale surface charge patterning was formulated, microfabrication techniques were optimized for features from 30 to 500mum, and the effects of surface charge heterogeneity were visualized. These endeavours culminated in the creation of a micro-mixer capable of decreasing required mixing channel lengths by up to 88% within the low Reynolds regime. Secondly, a stable gradient generator capable of producing controllable, complex gradients suitable for a wide range of analytes was presented. |
