Multiple fault diagnosis in digital microfluidic biochips

Abstract

Microfluidics-based biochips consist of microfluidic arrays on rigid substrates through which, movement of fluids is tightly controlled to facilitate biological reactions. Biochips are soon expected to revolutionize biosensing, clinical diagnostics, and drug discovery. Critical to the deployment of biochips in such diverse areas is the dependability of these systems. Thus, robust testing techniques are required to ensure an adequate level of system dependability. Due to the underlying mixed technology and energy domains, such biochips exhibit unique failure mechanisms and defects. In this article we present a highly effective fault diagnosis strategy that uses a single source and sink to detect and locate multiple faults in a microfluidic array, without flooding the array, a problem that has hampered realistic implementations of all existing strategies. The strategy renders itself well for a built-in self-test that could drastically reduce the operating cost of microfluidic biochips. It can be used during both the manufacturing phase of the biochip, as well as field operation. Furthermore, the algorithm can pinpoint the actual fault, as opposed to merely the faulty regions that are typically identified by strategies proposed in the literature. Also, analytical results suggest that it is an effective strategy that can be used to design highly dependable biochip systems.

Nonlinear Dual-Phase Multiplexing in Digital Microfluidic Architectures

“…Ultimately, one wishes to have maximal control over this fluid flow, and the standard structure for applying the spatially-defined voltage distribution has been the two-dimensional electrode matrix with square electrodes arranged in M rows and N columns [18,19]. Such a structure is shown in Figure 1(a) with two microdrops on a 16 × 16 grid.…”

“…The most general form for these on-chip operations, with the highest level of actuation freedom, is the two-dimensional square electrode grid [18,19]. Voltages are applied to individual square electrodes in a plane to draw microdrops into their neighbouring minimum energy positions.…”

“…On the other hand, such a configuration has practical limitations when implemented as an exceedingly large matrix. Grid structures beyond 5 × 5 [19] can become difficult to design and fabricate on the plane of the chip (if one wishes to avoid fabrication with underlying via holes). Each individual square electrode requires a separate electrical address line/input which must be patterned onto the actuating plane without crossing neighbouring electrodes or address lines.…”

A Novel Technique for Multiple Faults and Their Locations Detection and Start Electrode Selection in Microfluidic Digital Biochip

“…[4][5][6][7] The dropletbased chip is referred as \Digital Micro°uidic Biochip". 1 The latter one is advantageous over the continuous°ow Systems.…”

“…1 The latter one is advantageous over the continuous°ow Systems. 3,4,6 Correctness and Dependability are the important attributes for DMFB that are used as Medical Microsystems, for biomedical operation or safetycritical applications like point-of-care health assessment, massive parallel DNA analysis, automated drug discovery, air-quality monitoring, foodsafety testing, etc. Therefore, these devices must be tested after manufacturing and during bio-assay operations.…”