3-D In-Bi-Sn Electrodes for Lab-on-PCB Cell Sorting

We present a microfluidic lab-on-printed circuit board (PCB) device containing alloy vertical electrodes for sorting microparticles using dielectrophoresis. 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 on 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 into a PCB.