Sample preparation with multiple dilutions on digital microfluidic biochips

Digital microfluidic (DMF) biochips offer a versatile platform for implementing several laboratory based biochemical protocols. These tiny chips can electrically control the dynamics of nanoliter volume of discrete fluid droplets on an electrode array by application of actuation patterns. One important step in biochemical sample preparation is dilution, where the objective is to prepare a fluid with a desired concentration factor. The protocols implemented on DMF biochips may require several different concentration values of a sample. In this study, the authors propose a scheme to produce such target droplets from a supply of an input sample and a buffer solution. Simulation results show a significant amount of savings in the number of mix-split steps and waste droplets in comparison to other methods for generating multiple concentration factors.