Effect of Nanoparticles on the Suppression of Reagent Evaporation in Single-Plate EWOD System

This study investigates the modulation of thermal hydrodynamics of open droplets by nanoparticles (NPs) on a single-plate electrowetting-on-dielectric (EWOD) system. Experimental results show that the evaporation rate of deionized water was reduced about 66% by doping 800-nm SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> NPs as compared to that without NPs. Meanwhile, the decrease in contact angle was increased by 10° compared to that of pure DI water which is probably caused by the inclination of increasement in hydrophilicity with higher percentage of NPs doped. Specifically, Nanofluid exhibits improved wettability control, increasing pure water and, thereby significantly enhancing system energy efficiency. These findings demonstrate that the nanoparticle-enhanced single-plate EWOD system offers distinct advantages for point-of-care testing (POCT), particularly in microfluidic applications requiring precise thermal control and long-term operational stability.