High-resolution monitoring of liquid filling in microfluidics using capacitance measurements and longitudinal electrodes
We present a capillary-driven microfluidic chip with integrated electrodes and an Arduino-based electronic peripheral (<$50) for precise flow monitoring via capacitance measurements. Longitudinal electrodes patterned along the center of capillary pumps gave a good approximation of the liquid displacement with a resolution of less than 10 μm and did not adversely affect the autonomous filling of the pump with the liquid. The compact peripheral could easily fit inside a microscope or a reader and communicate with a smartphone. We demonstrated that anomalies during the liquid flow could be detected in real-time and the user could be warned promptly.