Mindy Simon

We present a microfluidic lab-on-PCB device containing alloy vertical electrodes for sorting microparticles using dielectrophoresis (DEP). The device consists of a hydrodynamic prefocuser and an electronic sorting region. Lining the two sidewalls of the electronic sorting region are regularly spaced rectangular metal electrodes reaching from the floor to the ceiling of the flow channel that bridge electric field lines laterally across the channel. The size and distribution of these vertical electrodes are arranged asymmetrically such that the resultant electric field forms sharp electric field gradients across the channel; specific geometries were optimized using finite element methods. Particles entering the device are initially focused into a single stream as they pass through the prefocuser. Subsequently, they are exposed to the lateral electric field gradient and separate into streams based on their size and dielectric properties. Validation was performed by dielectrophoretically separating live cells from dead cells. Importantly, the system presented can be readily integrated with various external sensors and actuators using commercially available components owing to the device's integration onto a PCB.

Dielectrophoresis (DEP) has proven an invaluable tool for the enrichment of populations of stem and progenitor cells owing to its ability to sort cells in a label- free manner and its biological safety. However, DEP separation devices have suf- fered from a low throughput preventing researchers from undertaking studies requiring large numbers of cells, such as needed for cell transplantation. We devel- oped a microfluidic device designed for the enrichment of stem and progenitor cell populations that sorts cells at a rate of 150,000 cells/h, corresponding to an improvement in the throughput achieved with our previous device designs by over an order of magnitude. This advancement, coupled with data showing the DEP- sorted cells retain their enrichment and differentiation capacity when expanded in culture for periods of up to 2 weeks, provides sufficient throughput and cell num- bers to enable a wider variety of experiments with enriched stem and progenitor cell populations. Furthermore, the sorting devices presented here provide ease of setup and operation, a simple fabrication process, and a low associated cost to use that makes them more amenable for use in common biological research laborato- ries. To our knowledge, this work represents the first to enrich stem cells and expand them in culture to generate transplantation-scale numbers of differentiation-competent cells using DEP. VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4902371]