Counterflow System Prototype Successfully Implemented
Hi all,
After a brief hiatus from winter break and my paper writing Mike and i have resumed our work on fabricating the counetrflow system, and we do have a success.
Fabrication:
The counterflow system is constructed based on oxide-layer protected pnc-Si, hosted within the V-notched Si-wafer that Dave specially produced for us.
The membrane side is bonded to a PDMS chamber with cylindrical holes for insertion of the fused silica capillary tubes for creation of the inlet and outlet.
The well side is first superglued to a glass slide, followed by insertion of the capillary tubes into the V-notches for creation of the inlet and outlet. The whole system is then sealed with vacuum grease.
Experiment:
The top chamber (sealed by the PDMS) is hooked onto the piezo-peristaltic pump that bumps 2.1 um beads toward the left (see the movie in result section). The bottom chamber (sealed by glass slide and vacuum grease) is hooked onto the piezo-peristaltic pump that bumps 15 um beads toward the right (see the movie in result section).
Result:
Video 1
video with z-axis microscopic sectioning up and down the counterflow system. The top shows 2.1 um beads flowing from right to left. The bottom shows 15 um beads flowing from left to right. The original acquision frame rate is 3 fps, the playback shown in this video is 7 fps.
Video 2
hm-counterflow-2-jan-14-2009-7-fps
Essentially the same as Video 1, except this time we can also see the 15 um beads stuck to the surface of the glass slide at the bottom. This time the acquisition frame rate is 20 fps. The playback rate of this video is slowed down to 7 fps so we can see better what’s going on.
Support Materials:
This is terrific! Congrats guys.
I love how parallel the flow is. I don’t understand why the flow isn’t right up against the membrane. I can’t tell when you are in PDMS vs. the silicon well.
And lets calculate the flow rate from the bead velocity!