[DIYbio] Re: copper etched microfluidics?

Yes, see the below.  I etched my own boards for the setup.

http://88proof.com/synthetic_biology/blog/archives/280

 

Longest run of a droplet I was able to get was 7 pads before exploding or evaporating or sticking.  Be prepared to etch a lot of boards because any surface contamination or voltage fluctuation could cause arcing which will likely pit the copper edges and degrade the charge plates.  Also it is difficult to etch these boards because the pads need to have precise sizes and gaps -- that is, if you want repeatable results.  (For publishing a paper in a journal, you don't really need repeatable results or reasonable yield.. apparently.)  So it doesn't work reliably unlike as described in the paper (go figure..).  The hydrophobic surface is the difficult part, and also droplet evaporation.  Perhaps in a controlled chamber, it might be more interesting. If you have a spin coater, you can try making very thin polymer films for the PCBs.  The journal paper used a particular brand of saran wrap.  I had a few thicknesses made by the univ. chem-e lab, and they were all too thick to get good droplet movement.   There's some videos on Lab-on-a-Chip journal where a lab fabricated flex circuit ($$$) and was apparently able to get a droplet to move significant distances, the electrical switching was performed by hand (aka:  undergrad touching wires together or something).  At some point of scale really becomes a horrible routing problem of PCB traces and the only way around it is with vias and busses and.... well it might be worth it, if the method worked at all, which it doesn't, practically speaking.

You can also try the very high voltage power supply I rigged up for running the PCB, below.  (Just don't kill yourself.)  The voltage is not super accurate but neither is the humidity in a lab, ha.

http://88proof.com/synthetic_biology/blog/archives/303