Enhancing Water Droplet Movement on Digital Microfluidic Platform using Replaceable Dielectric Layer and Natural Hydrophobic Lubricants

Digital microfluidics (DMF) involves manipulating small liquid droplets on a surface by utilizing electric field, enabling movement of fluid element. DMF allows for intricate biochemical tests and diagnoses on a small scale, leading to less use of reagents and improved efficiency. However, there is an issue with the use of costly fabrication process of its various layers, especially the dielectric film. Hence, in this study, we propose a unique DMF platform based on the electrowetting on a dielectric (EWOD) using a PCB substrate and grafting tape as dielectric film. The platform's performance in terms of droplet actuation was investigated at various DC voltages ranging between 300 and 450 volts. Using easily accessible, naturally extracted, and reasonably priced materials like silicone oil, canola oil, mustard oil, sikakai oil, olive oil, and castor oil with grafting tape as a dielectric layer, simplified and reduced the cost of the production process. Sikakai oil produced the maximum droplet velocity when utilized for droplet actuation in comparison to other oils used during experimentation. Our proposed platform has the potential to be used in EWOD based applications, including medical diagnostic applications such as clinical, chemical, biological, and environmental sensing of various pollutants.