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The Experiment, from start to finish

In order to start this process, I learned how to mix a polymer based elastomer (fancy name for a mold).  The master mold was imprinted or etched in the clean room before I arrived.  It was then poured, allowed to cure, and the channel was ready to be trimmed from its master mold.  Once it was trimmed, it had 2 holes punched into it so there was a way to deliver fluid into the channel. 

The channel was then placed onto a slide that already had pieces of conducting copper tape attached.  The assembled slide was placed in between a Plexiglas vice, holed together at the corners by screws.  The holes were lined up with the electrode and the channel was filled with a buffer solution in order to keep the pH constant within the channel. 

Once that was done, C. elegans was harvested from the culture dish... infused into the opening of the channel so the worms could swim freely until the electric field was applied.

Once several of the more robust swimmers were monitored...

the electric field would be supplied by a voltage source (0-25 V).  Once the field was steady, it would be reversed periodically in order to determine the effect on the worm.


All of this would occur, and examples of electrotaxis would be recorded by the camera for analysis later on. The effect of the boundary was thought to be an influencing factor, and therefore a way to measure the speed was the goal.  Below is a picture of the swimmer taking the turn.

As you can see in the captured still, there are 2 apparent swimmers, both near the boundaries.  Within the actual PDMS channel, you'll notice all sorts of spots- these are defects and blemishes in the mold or possible pieces of dust that were unable to be removed without destroying the PDMS channel.