Digital microfluidic biochips: Recent research and emerging challenges

Microfluidic biochips are replacing the conventional biochemical analyzers, and are able to integrate on-chip all the basic functions for biochemical analysis. The “digital” microfluidic biochips (DM-FBs) are manipulating liquids not as a continuous flow, but as discrete droplets on a two-dimensional array of electrodes. Basic mi-crofluidic operations, such as mixing and dilution, are performed on the array, by routing the corresponding droplets on a series of electrodes. The challenges facing biochips are similar to those faced by microelectronics some decades ago. To meet the challenges of increasing design complexity, computer-aided-design (CAD) tools are being developed for DMFBs. This paper provides an overview of DMFBs and describes emerging CAD tools for the automated synthesis and optimization of DMFB designs, from fluidic-level synthesis and chip-level design to testing. Design automations are expected to alleviate the burden of manual optimization of bioassays, time-consuming chip designs, and costly testing and maintenance procedures. With the assistance of CAD tools, users can concentrate on the development and abstraction of nanoscale bioassays while leaving chip optimization and implementation details to CAD tools.