Biomedical sensors using microfluidic channels are prone to blockage due to particles and bubbles in the fluid. Wider channels may be used, but wide polymer channels may suffer from structural instability (e.g., sagging channel covers). A common design uses many parallel flow channels separated by structural support walls, but these can be rapidly blocked by particulates. We have been studying an alternative “Cathedral Chamber” design where the channel “roof” (cover) is support by periodic posts which creates many possible flow paths to bypass blockages. We use Monte Carlo modelling with iterative COMSOL fluid dynamics simulations to establish the stream lines, and particle velocities. Then a rules based methodology iteratively places trapped particles based on the fluid paths created by the existing blockages, until the system become fully blocked. Previous work has shown that the periodic post design increases lifetime by allowing 6 to 7 times more blockages than can a parallel channel design. In this paper, we simulate and analyze why expanding the number of channels increases almost linearly the number of particles required for blockages. Lifetime increase is still 4.5-5.5 times even for the limiting case of a 2 channel cathedral chamber. This shows the sideways flow created by the periodic posts creates many advantages for the microfluidic chambers.
Glenn H. Chapman and Bonnie L. Gray, "Enhancing defect tolerance in periodic post microfluidic channels," Proc. SPIE 9705, Microfluidics, BioMEMS, and Medical Microsystems XIV, 97050M (Presented at SPIE BiOS: February 14, 2016; Published: 18 March 2016); https://doi.org/10.1117/12.2223451.
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