The purpose of layering Sylgard on electrode is not an insulation (glass is already a perfect insulator), but decreasing a capacitance of electrode (and thus making a noise coming from electrode smaller). You may try to choose a capillars with thicker wall or smaller inner diameter. I have heard that some uses the nail varnish
Hi Euan,
we use dental wax for coating or we dip the filled patch pipettes for a few seconds in Sigmacote.
Regards,
Matthias
I have used Sylgard as Evgeny Petrov said above. You can do as he said.
Euan,
In addition to all above mentioned, you may try to use not borosilicate glass capillars, but quartz ones. It's more expensive and needs a laser puller, but electrodes will generate much smaller noise, what is very critical if you deal with currents of 1-2 pA
Yes, for very small currents (single-channels) you need quartz and sylgard I believe so that your capacitance and noise are very small. If you are just looking to insulate your electrode to changes in capacitance (say from a slightly unsteady bath level on a slice setup) then parafilm is great. Cut a little strip about 6mm by 2 cm long and pull it around the pipet up the shaft at an angle until it almost touches the tip then wrap it back down in similar spiraling fashion. It'll take a bit of practice but I've wrapped electrodes to within 10um of the tip and it works almost as well as sylgard. It is much faster and cheaper and easier and insulates really well from capacitance changes.
To minimise stay capacitance use molten ski wax, painted on the electrode using a clean soldering iron. Simple & quick. Been using it without problems for 20 years.
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