A high-precision nanoliter droplet dispensing system based on optoelectrowetting with tunable droplet volume

The capacity to generate high-precision droplets within Lab-on-a-Chip (LOC) devices is essential for numerous biochemical applications, such as DNA sequencing and drug delivery. In this study, we introduce an optoelectrowetting (OEW)-based droplet manipulation system that utilizes a novel droplet dispensing strategy, enabling precise nanoliter droplet dispensing with tunable droplet volume. The system comprises an OEW microchip, a liquid crystal display (LCD) projector connected to a laptop for generating customized light patterns, and a microscope equipped with a charge-coupled device (CCD) camera mounted above the OEW microchip for real-time observation. Simulations and experiments were conducted to investigate the optimal conditions for high-precision droplet dispensing. The system demonstrated exceptional stability in generating uniform droplets, with a minimum relative error (RE) of 0.45% and coefficient of variation (CV) of 2.49% for dispensing droplets of a volume of 36.52 nL. An experiment was conducted to dispense droplets of varying sizes, demonstrating the system’s exceptional capability to generate droplets across a broad size range. The system was further validated through its application in polymerase chain reaction (PCR) amplification, confirming its performance in small-scale biochemical reactions. The results indicate that the proposed OEW droplet dispensing system is highly proficient in generating high-precision small-scale droplets with tunable volume. It also demonstrates its capability for biochemical processing and superior performance in sub-200 nL droplet dispensing compared to conventional pipetting techniques. This advancement holds significant potential for enhancing the performance and efficiency of LOC devices in biochemical research and clinical applications. (Figure presented.)