Biomedical Engineering Reference
In-Depth Information
TAble 2.1
Experimentally Characterized Module Library for Synthesis
Operation
Resource
Time (s)
DsS; DsB; DsR
On-chip reservoir/dispensing port
7
Dlt
2 × 2 array dilutor
12
2 × 3 array dilutor
8
2 × 4 array dilutor
5
4-electrode linear array dilutor
7
Mix
10
2 × 2 array mixer
6
2 × 3 array mixer
3
2 × 4 array mixer
4-electrode linear array mixer
5
Opt
LED + Photodiode
30
Storage
Single cell
N/A
be different [9]. A binary dilution operation can also be easily implemented
by mixing of sample droplet followed by droplet splitting. Absorbance of the
assay product can be measured using an integrated LED-photodiode setup.
Experiments indicate that this absorbance measurement takes 30 s.
The microfluidic module library for a protein assay is shown in Table 2.1.
A total of 122 interdependent module pairs must be routed for this protocol.
Clearly, the large number of droplet transportation operations in this proto-
col makes it difficult for a biochemist user or a postsynthesis design tool to
determine transportation paths. We also need to specify some design param-
eters for the biochip to be synthesized. Different design specifications can be
determined based on user needs and manufacturing constraints.
2.4.1 results for routing-Aware Synthesis
We first evaluate the proposed routing-aware synthesis method described
in Section 2.2. We apply it to an example in which we set the maximum
microfluidic array size to be 100 cells, and the maximum allowable comple-
tion time for the protein assay to be 400 s. We assume that there is only
one on-chip reservoir/dispensing port available for sample fluids, but two
such ports for buffer fluids, two for reagent fluids, and one for waste fluids.
Finally, we assume that at most four optical detectors can be integrated into
this biochip.
We first use the routability-oblivious PRSA-based algorithm from [15] to
find a desirable solution for the protein assay that satisfies design specifi-
cations. The solution thus obtained yields a biochip design with a 10 × 10
microfluidic array, an assay completion time of 377 s, a maximum module
distance of 14 electrodes, and an average distance of 3 electrodes.
Next, we use the droplet-routing-aware synthesis method using the pro-
cedure of Figure 2.3. The procedure yields a biochip design with a 10 × 10
