Fundamentals and applications of digital microfluidics based on electrowetting-on-dielectric

Digital microfluidics (DMF), an emerging technique for precise control of discrete droplets on an electrode array at the micro- and nano-scale, has attracted significant attention due to its minimized sample consumption, high analytical efficiency, and easy system integration. It has shown promise in sample preparation for biomedical and chemical analysis. Hereby, we present a focused review on DMF based on electrowetting-on-dielectric (EWOD). It begins with an introduction to the fundamental concepts of surface energy (surface tension and wetting phenomena), followed by an exploration of the working principles and historical development of EWOD. An in-depth analysis of the physical models that govern microfluidic dynamics, is then presented. Based on the demands of practical applications, the status and trends of material selection, chip fabrication, and integration have been summarized and assessed. In addition, the artificial intelligence (AI)-assisted explorations and representative applications have been analyzed. In view of the existing problems and challenges, possible solutions are also proposed. This review facilitates the understanding of the EWOD-DMF and its practical applications, providing a useful tool and inspiration for future technological innovation.