simple alignment tool for microfluidic assembly

Hi all,

This post showcase a simple (low-tech) alignment tool for assembling the different components of a microfluidic chamber.

Essentially, the alignment pieces are made from two index papers cut using the Silhouette Cameo. The two cut index papers are bonded together using double-sided tapes.


The square holes are where the membrane chips are to be dropped in. The much smaller circular holes are used for aligning the cut index papers during the bonding. 4 metal pegs are drilled into a plastic piece to guide the alignment of the cut index papers to be bonded. The 4 metals pegs are made from 1 inch long 19 gauge blunt needle [from BRICO Medical Supplies Inc], I think the outter diameter is ~1.28 mm. I think 3/64″ (1.19 mm) drill bit are used to create the holes in the plastic piece (will update the info once i confirmed the drill bit size).

Here is a little close up view:

within the square holes you can actually see the silicone gasket that is to be bonded to the membrane chip. The silicone gasket (100 μm thick) is also cut using the Silhouette Cameo. NOTE: During the cutting, the top plastic cover piece is not removed! Cutting Blade Setting = 2. Software Setting: Blade = 3, Speed = 1; Thickness = 20; Overcut enabled = 0.1 mm. Dimension-wise, the square holes (5.5 mm x 5.5 mm) are 0.1 mm bigger than the membrane chip (5.4 mm x 5.4 mm)

Example of a piece of gasket bonded to the chip:

When I designed cut pattern for the silicone gasket I shifted the design the wrong way. For the next gasket I will shift the design back correctly.

This is a work in progress. Shown below is the transparency mask for photolithographing a SU-8 mold.

This SU-8 mold will be used to pattern PDMS. The PDMS will be bonded on top of the membrane chip that is bonded to the silicone gasket.

I will update this post once I have all the components ready. This will include an update on the tolerance of this alignment method.