Automated, accurate, and inexpensive solution-preparation on a digital microfluidic biochip

Solution-preparation is a basic and repetitive step for many biological and chemical experiments in the laboratory. It uses stock solutions of sample, reagents, and diluents to derive various mixed solutions with the required concentration levels. Manual solution-preparation methods are time-consuming, imprecise, and they require large volumes of liquid. We propose an electrowetting-based ldquodigitalrdquo microfluidic biochip design for automated solution-preparation. An efficient solution-preparation algorithm is also presented to generate a preparation plan that lists the intermediate mixing steps needed to generate the target solutions with the required concentrations. It determines the type, concentration, and the number of dispensed droplets of stock solutions. The proposed automated solution-preparation algorithm and biochip platform are evaluated using a protein-crystallization application.