A new customized testing technique using a novel design of droplet motion detector for digital microfluidic Biochip systems

Digital microfluidic biochip (DFMB) systems have been developed as a promising platform for Lab-on-chip systems that manipulate individual droplet of chemicals on a 2D planar array of electrodes. Because of the safety critical nature of the applications these devices are intended for high reliability and thereby dependability becomes a major issue for the design of DMFBs. Therefore, such devices are required to be tested frequently both off-line (e.g., post-manufacturing) and prior to each assay execution. Under both scenarios, testing is accomplished by routing one or more test droplets across the chip and recording their arrival at the scheduled destination. In this paper, we have proposed a new design of a droplet motion detector based on capacitive sensing, which can be manufactured with the cell electrodes for detection of the presence (arrival) of a droplet at a predetermined location. Using this sensor, we have further proposed a customized testing technique for a specified layout with an objective of 1) optimizing the total number of test droplets for testing a particular bioassay, 2) optimizing the number of dispensers, 3) minimizing the overall test completion time, 4) detection of a specific segment at fault within the given layout, and 5) optimizing the number of locations where the detectors are to be activated. The test simulation has been carried out on two testbenches of Benchmark suite III and the results are found to be encouraging compared to the existing methods.