The University of California, San Diego hosts an industry-sponsored series of senior projects once a year. Mine was sponsored by the UCSD Department of Cellular and Molecular Medicine, which was in the process of studying the effects of various substances on the rate of leukocyte (white blood cell) transmigration (transfer) through endothelial layers (blood vessel walls).
Traditionally, examining this sort of process in a dynamic environment was done solely with in-vivo (live rat) studies, which made observation via microscope exceptionally difficult. A previous UCSD group had developed a simple device that allowed the researchers to view adhesion (sticking) of the leukocytes to the endothelial layer (which was grown on a flexible porous membrane).
This was sufficient for observing adhesion, but studying actual transmigration was impossible, as the membrane was placed flat against an acrylic block, leaving nowhere for leukocytes to go. Our group's goal was to find some way to collect the leukocytes that passed through the membrane for counting, in order to determine the rate of transmigration.
This was a difficult task, as laminar (straight-line) flow required that the membrane remain flat - impossible under the pressure of the fluid passing over it. Our solution to the problem was to create a second, parallel flow of fluid on the underside of the membrane, pumped by the same motor through the same lengths of tubing in an otherwise isolated circuit, thus having the same pressure.
The final design of the chamber itself was left up to me. I machined it out of half-inch clear acrylic, which allowed for a microscope to be focused on either side of the membrane, to observe either side of the transmigration process. Two side-caps allowed the assembly to snap together, and the plumbing fixtures allowed quick connection of the necessary apparatus.
All that was left was to machine it...
The sponsors gave us full marks for our work on this project, satisfied with what we'd produced. (Personally, I think it looked kind of chintzy, and would have like to have gone back and styled it a bit, but scientific research insitutions rarely go out of their way for aesthetics.)
If you're interested in learning a little more background on the biology at work, or the system itself, feel free to check out the group's final summary report.