Biomedical Engineering Reference
In-Depth Information
The proposed test methods facilitate defect screening, which is necessary
to ensure dependable system operation. However, the effectiveness of these
test techniques is limited by the fact that they do not consider testability. To
address this problem, design-for-testability (DFT) techniques are presented
in this topic for digital microluidic biochips. A DFT method is described to
incorporate a test plan into the fluidic operations of a target bioassay protocol.
By using the testability-aware bioassay protocol as an input to the biochip
design tool, the proposed DFT method ensures a high level of testability. A
Euler-path-based functional test method, which allows functional testing for
irregular chip layouts, is also presented.
The preceding design automation and testing tools are utilized to design
microfluidic biochips for protein crystallization, an important laboratory
technique for understanding the structure of proteins. A multiwell high-
throughput biochip chip design for protein crystallization is proposed. The
chip design is optimized using the proposed Connect-5 pin-constrained
design method, which achieves a significant reduction of input bandwidth
without loss, thereby reducing the fabrication cost. With the help of an effi-
cient well-loading algorithm for parallel manipulation of multiple droplets,
the optimized pin-constrained design maintains the same level of operation
concurrency as a direct-addressed design. Finally, defect-tolerance tech-
niques are presented to ensure the functionality of the chip under the con-
dition of defects. The preceding design automation and optimization tools
help deliver an efficient, cost-effective, and reliable design of a biochip plat-
form for protein crystallization, which is ready for manufacture as well as
easy to use and maintain after it is fabricated.
The rest of this chapter is organized as follows. Section 1.1 presents an
overview of digital microfluidic technology. Section 1.2 discusses synthe-
sis, testing, and pin-constrained design techniques. Section 1.3 presents an
overview of protein crystallization and design automation tools for protein
crystallization chip design. Finally, an outline of the topic is presented in
Section 1.4.
1.1 Digital Microfluidic Technology
Traditional microfluidic technologies are based on the continuous flow of
liquid through etched microchannels on a glass or plastic substrate [4,21].
Pumping is performed either by external pressure sources, integrated
mechanical micropumps, or electrokinetic mechanisms. These systems
are often operated in a serial mode where samples and reagents are loaded
into one end, and then moved together toward an output at the other end
with mixing, sample injection, and separations occurring at (structurally)
predetermined points along the path. These systems are adequate for many
