Parallel Scan-Like Testing and Fault Diagnosis Techniques for Digital Microfluidic Biochips

Dependability is an important attribute for microfluidic biochips that are used for safety-critical applications such as point-of-care health assessment, air-quality monitoring, and food-safety testing. Therefore, these devices must be adequately tested after manufacture and during bioassay operations. Moreover, since disposable biochips are being targeted for a highly competitive and low-cost market segment, test and diagnosis methods should be inexpensive, quick, and effective. We propose a cost-effective testing methodology referred to as "parallel scan-like test", and a rapid diagnosis method based on test outcomes, for droplet-based microfluidic devices. The proposed method allows testing using parallel droplet pathways in both on-line and off-line scenarios. The diagnosis outcome can be used to reconfigure a droplet-based biochip such that faults can be easily avoided, thereby enhancing chip yield and defect tolerance. We evaluate the proposed test and diagnosis methods using complexity analysis as well as experiments using a fabricated biochip.