Troubleshooting

Troubleshooting Electrical Recordings in DHBs

Stabbing issues:

Can’t penetrate the droplet because it moves around when you try to stab it? Not enough agarose on the tip of the stabbing electrode. Also, leaving the electrode in a lipid solution so that it gets coated with lipids will make it harder to stab, so clean well with ethanol prior to dipping in agarose.

Droplet creeps so far up the electrode on stabbing that the bilayer disappears? Too much agarose on the tip of the stabbing electrode. Over time you might find a build-up of old agarose that is hard to wash off with ethanol. Try cutting off the tip and re-treat with 30% sodium hypochlorite over night.

Electrical Noise Issues:

Make sure the lid on the faraday cage is completely closed, and that it is properly earthed. Make sure the microscope is turned off at the wall. Try turning off the light and other electrical appliances at the wall (including the DSLR camera, if it is there). Re-treat your electrodes with 30% sodium hypochlorite over night.

As a bench mark, you should expect an IRMS value of ~5 pA in bay 6 or ~10 pA in bay 4.

Electrical drift:

Can be compensated for by adjusting the Pipette Offset. This is not ideal, as it is effectively applying a potential to compensate for an ionic imbalance across the bilayer, so any potential you apply will be in addition to the pre-existing one.