An Integrated Electronic Meniscus Sensor for Measurement of Evaporative Flow

This paper presents an electronic sensor for evaporative flow measurements in open microfluidics Lab-on-Chips. It is based on a novel PCB technology especially developed for biomedical devices. The proposed technique takes advantage of the correlations between the height of the meniscus and the evaporation rate, which in turn allows to calculate the flow speed inside the channel, and that of the impedance between two electrodes on the top of a microwell with the meniscus height. The sensor can be integrated in devices composed of large arrays of microfluidic channels. Experimental measurements show that the device is sensible for flow speeds ranging from 0.4 to 0.8 μm/s at room temperature and atmospheric relative humidity.