Modelling, detection and diagnosis of multiple faults in cross referencing DMFBs

In recent time´s digital microfluidics have gained much attention as an emerging technology that provides automation in fluid handling within a miniaturized substrate. Compared to traditional bench-top procedures, microfluidic biochips offer the advantages of low sample and reagent consumption, less likelihood of error due to minimal human intervention, high throughput, and high sensitivity. With the increase in number of bioassays for concurrent operation to be mapped in a single digital microfluidic platform needs for design automation as well as testing and fault diagnosis techniques become highly relevant for better accuracy in results and efficiency in operation. In spite of individual and independent control of electrodes -a new droplet manipulation method based on a “cross-referencing” mode that uses “row” and “columns” to access electrodes has recently come into use. The cross referencing technology largely scales down the control pin number on chip, which not only brings down manufacturing cost but also enables larger number of bioassay integration on a single biochip platform. However, the cross-referencing scheme due to severe electrode interference and other defects can result in faulty operations which in turn cause erroneous results or complete malfunction of the device. In this paper we tried to identify specific types of faults that may occur in cross referencing biochips and developed techniques for detection and location of such faults with the objective of (i) optimum resource utilization and (ii) minimum consumption of time. Testing simulation has been carried out with different size of 2D grids and with different number of test droplets and the corresponding results are found to be encouraging.