[Neuroscience] Re: Aspiration of buffer during electrophysiology

Bill via neur-sci%40net.bio.net (by connelly.bill from gmail.com)
Sun Aug 5 22:54:43 EST 2007


Thanks for the tips Trevor.

On Aug 6, 10:53 am, Trevor Lewis <t.le... from unsw.edu.au> wrote:
> Dear Bill,
>
> I have a couple of tricks that I use to reduce both the electrical
> noise and the changes in bath solution level. Rather than use a very
> high suction rate to break-up the solution into beads, I place a
> bubble trap close to the microscope stage, with a short length of
> tubing going to suck solution off from the bath. The bubble trap is
> nothing special - a cut-down 5 ml syringe with a rubber stopper in
> the open end and a hypodermic needle going through the stopper. That
> way there is a luer fitting on each end to connect the tubing. The
> important aspects are 1) to keep the line from the bath to the bubble
> trap short, and 2) to keep the bubble trap close to the grounded
> (shielded) environment of the stage. I usually find that placing the
> bubble trap just below the level of the stage and towards the rear is
> a good position. We've used several methods of attaching the bubble
> trap, including velcro (the velcro with adhesive on one side) and
> sometimes there is a convenient structure to strap the bubble trap to
> with cable ties.
> The second trick is having a sloping surface at some location that
> enters the bath and then locating your suction pipe so that it sits
> flush (parallel) to this sloping surface and just comes into contact
> with the solution. This setup uses surface tension to your advantage
> rather than trying to work against it. I haven't played around a lot
> with the angle of the sloping surface; I use around 40 deg above the
> horizontal.
> With both these tricks I find that I can get away with a much less
> powerful suction and still get efficient solution exchange.
>
> This works for me, but like a lot of things in electrophysiology,
> there is always more than one way that works.
> Good luck.
>
> Trevor Lewis




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