A Multi-Stage Micro-Tangential Flow Filtration System for BioMEMS Applications

The micromachining technology that emerged in the 1980s has yielded an explosion of developments of micro electromeclianica1 systems (MEMS) in the past two decades. The developments have brought lives to many miniaturized sensors and actuators. At the same time, a new frontier in micro-scale fluid flow study has also obtained considerable attentions, not just for understandingthe multi-physics nature of individual MEMS devices but also to renovate new applications that utilize micro-scale flow. Toward the BioMEMS application developments in using micro-scale flow, the idea of lab-on-a-chip or micro total analysis systems (uTAS) comes into sight: an ultimate goal of which a single chip-based platform or system can process and analyze biological sample fluids as done in present biochemical and pharmaceutical laboratories, yet at a very miniaturized scale. Preparing in small amounts of sample fluids has yet become a major challenge. Separation of heterogeneous solid contents in a solution, as one of the first and important steps in sample solution preparation, is a processing function inseparable in any true and totally integrated lab-on-a-chip development. Several groups [I, 9, 22] have designed filtration devices that utilizebasic flow-through filtration concepts. Tangential flow filtration, another mechanical filtration method that is widely used in large-scale nano-particle separation, has not been extensively exploited in pTAS [2]. The objective of this project is to present a new ~iiicromacliined submicron- filtration device that incorporates tlie sclienie of tangential flow filtration. Results from this micro-tangential flow filtration device show its ability to overcome some of the problems that exist in the flow-through type of micro-machined filters, and has rooms for integration into different BioMEMS applications.