Cell Detection
Inertial microfluidic provides a solution for fast and easy cell/particle separation by eluting cells from special designed flow channels at different rates and positions. However, to quantify the separation and therefore determine its effectiveness, the eluted cells must be collected and characterized using instrumentation such as a flow cytometer. This extra step prevents the inertial microfluidic from being a fully integrated cell sorting platform. In this project, inertial microfluidic channels are combined with an end detector that is capable of  quantifying cells based on not only cell characteristics (e.g size), but also their positions inside the channel. Microelectrodes are used to perform impedance flow cytometry (IFC) for detection. This provides many unique advantages compared to other methods including: 1) label-free, 2) low-cost, 3) small-footprint, 4) easy system integration into both the channel and electronics, 5) multiplexing potential. The cell detection is realized by measuring the transient impedance at the electrodes corresponding to cell passages.  The position detection is realized by manipulation of electrode geometry to create an electric field gradient along the desired direction. Since the current is proportional to the electric field strength, the position difference thus produces differences in signal amplitudes.