A Digital Microfluidics System with Closed-Loop Feedback Droplet Sensing

In this paper, we present a digital microfluidics (DMF) system with closed-loop feedback droplet sensing. The system is capable of controlling the movement of droplets and detecting their positions in real time, and is compatible with different numbers of DMF electrodes. The detection of the droplet position is realized by impedance sensing. When an electrode failure occurs, the system automatically performs path planning to move the droplet successfully. Besides, we designed a voltage control unit (5V DC/AC to 80V DC/AC) to realize the voltage control for different droplets. The experimental results show that the droplet position detection time is about 2 ms, and the detection accuracy reaches 100% at 100 times. With the help of the droplet sensing system, even there’s an ineffective electrode in the origin path, the droplet was able to move to the target electrode by the replanned path. The system is expected to play an important role in many biochemical experiments due to its automation and reliability.