Pulling Electrodes & Other Musings

What I thought initially would be hard, proved to be exceptionally easy then exceptionally impossible.  I’d heard from others long before I’d gotten into the business of pulling my own electrodes that this would be a road fraught with dismay and frustration, or at least fraught with cursing and many discarded electrodes that did not work out.  When I started in on this, I got our lab’s shared laser puller up and running.  This part wasn’t hard, and merely required reading the directions.  Then after less than half a day of pulling electrodes, I was getting ones that were around 30-40 Megohm.  What, I found soon after, however, was that that was 30-40 Megohm with a tiny bit of air still holding out near the tip, and that filling the very tip of the electrode by capillary action is necessary to get a proper electrode.  As an aside on this matter, if you have crazy noise issues that creep into your signal and you’re sure it isn’t clogged: you may have a bubble in there somewhere.  It seems however, that getting this capillary action going becomes exponentially harder and slower as the tip diameter closes down.  Currently, this is showing itself in the sense that I can only get 4-10 Megohm micropipettes that actually sip from the KCL I’m placing them in.I’m writing this, and posting it, both for my own reference, and for the fact that I couldn’t really easily find anything on methodology for pulling electrodes.  Perhaps I should start a wiki for such things?  It would not have to be limited in scope only to that particular topic, but rather be a site covering lab technique and the various ins and outs.  Personally, this rather appeals to me for the reason that a lot of the manual lab work requires what seems to be almost a black art, and either someone in your lab can show you this art, to some extent, or you just have to spend enough time banging into things that you figure it out on your own.  I will have to think about this…