BME Seminar Series: Jessica Snyder

Molecularly Thin Nanoporous Membranes as High Performance, Low Voltage Electroosmotic Pumps

Supervised by Professor Jim McGrath

Abstract

Porous nanocrystalline silicon (pnc-Si) membranes are ultrathin, nanoporous membranes that exhibit high water permeability and enable sharp molecular separations by diffusion and pressurized flow. These observations have been attributed to the small thickness (5-30 nm) and well-defined nanopores in this material. During experiments in which pnc-Si membranes were used as barriers for electrophoresis, it was accidently discovered that pnc-Si membranes produce high electroosmotic flow rates, indicating that this material could be used to fabricate electroosmotic pumps (EOPs) for microfluidic devices. In this work, we have studied the intrinsic electroosmotic flow rate of pnc-Si membranes and the effect of surface modifications on the material. The small thickness of the material enables high electric fields, and high flow rates can be achieved with low applied voltages. We demonstrate the applicability of pnc-Si membranes as EOPs in a simple microfluidic device, and we measure the transport of nanoparticles using particle tracking algorithms. Pnc-Si membranes are an enabling technology, and on-chip EOPs fabricated from pnc-Si may lead to increased ease of manufacture and portability of diagnostic microfluidic devices.