Pin-Constrained Designs of Digital Microfluidic Biochips for High-Throughput Bioassays

Digital microfluidic(DMF) biochips have emerged recently as a viable platform of implementing conventional laboratory-based biochemical procedures. These tiny chips are able to manipulate nanoliter volume of discrete fluid dropletson an electrode array via electrical actuation. However, with the increasing dimension of the array, the number of external control pins connected to the electrodes may increase significantly. Several pin-constrained biochip design techniques have been proposed earlier for controlling the electrodes through a small number of pins, a short review of which is presented in this paper. An important design problem in such a chip is interconnection wire routing for the identically controlled electrodes. To address this problem, we propose a new scheme of layered wire routing for a special class of pin-constrained biochips that can concurrently execute multiple instances of the same bioassay to increase throughput. We also describe a hierarchical routing scheme to ensure scalability.