Biomedical Engineering Reference
In-Depth Information
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Figure 2.6
A 3-D model illustrating the synthesis results: (a) routing-oblivious method of [15]; (b) the
proposed method.
microfluidic array, a completion time of 378 s, a maximum module distance
of 7 electrodes, and an average distance of 1 electrode. The computation
time for the routability-oblivious and routing-aware methods for the protein
assay are 4 min and 5 min, respectively on a 3.00 GHz dual-core Intel Xeon
server with 4 GB of RAM.
We illustrate the synthesis results, that is, assay operation schedule and
module placement, using a 3-D box model shown in Figure 2.6. Each micro-
fluidic module is represented as a 3-D box, the base of which denotes the rect-
angular area of the module and the height the time span of the corresponding
assay operation. The projection of a 3-D box on the X-Y plane represents the
placement of this module on the microfluidic array, while the projection on
the Z-axis (time axis) represents the schedule of the assay operation. Note that
the synthesis results determine the locations of the integrated optical detector.
Transparent electrodes for optical detection are used in the microfluidic array.
Although the two designs have comparable area and time cost, the
routing-aware synthesis method leads to a 50% reduction in the average
and maximum module distance. This indicates a significant improvement
of routability and reduction of the time cost for carrying out droplet routing.
To verify this improvement, we applied the postsynthesis routing method
of [27] to find efficient droplet pathways routing for both layouts. We find
that while routing-aware synthesis easily leads to a feasible routing plan, the
layout for the routing-oblivious result is not routable; that is, no pathway is
available for certain droplet manipulations. Figure 2.7a shows a snapshot of
the layout for the routing-oblivious result taken at time instant 297 s. In this
snapshot, a droplet is to be routed from the storage unit S
1
to dilutor D
3
,
which is located 7 electrodes away in the routing-oblivious layout. However,
as shown in Figure 2.7a, there is no pathway available for routing due to the
compact layout and large module distance. In contrast, in the layout derived
from the routing-aware synthesis procedure, since the average module
