I had originally underestimated this part of the design. I had thought that a few wires spaced close enough that a fly lands on two at any given time will be easy to fabricate. With this in mind, I (with some help from fellow primates) meticulously placed thin copper wires on a plastic sheet. The edges were glued with silicone(as it had to be non-toxic and resistant to alcohol which would be used to wash the apparatus quite frequently). This sheet was then folded into a cylinder and placed into a disposable syringe as shown in the picture. This is where it all fell apart. The wires shorted, a few came off while others deformed. A major problem seems to be the fact that thin copper wires offer too little surface area for adhesion.

Right now I have two options in mind:

1) Use conductive copper tape(cheap but i have no idea how I am going to cut it into thin strips)

2) Use copper nanoparticle based conductive ink suspended in a two part epoxy. ( cheap and sexy but drawing thin lines with that will be challenge. The issue of durability on a plastic substrate is also an area of concern)

I would really appreciate any and all suggestions that does not involve ordering a custom flexible PCB from China.