first: when pipette touch cell, I can see a increase of the resistance, but at the same time the baseline whobble greatly. I orignally think I press the cell too much, but even I slightly move the pipette onto the cell, the baseline also wobble greatly. can you teach me how this happen ?
second: it need too long to establish the G ohm seal seal, about 5 minutes or even more. I think this is not correct.I do not know why
third: mostly, this is the most distriuting point. I can not eatablish G ohm seal, always about 40-50M ohm, then seal stop increasing. I further sucked, but not increase of seal, still about 40-50M ohm. at this moment, I find there is much of cell membrane-likes in the pipiette. when I lift up the pipette, there left a relative long and thin "tail" on the brim of cell (just like "Q" as you imaging). more strongly suck, more lone of this type of tail, but the seal can not increase.
I have check my system, not air leak.
so please help me.
to help you i need to know first what the resistance of your pipette tip is before you patch, when it is just dipped in the ECF.
Also what is the inner diameter of the tips after you have pulled the glass?
What are the compositions of your extracellular and intracellular solutions?
What type of cells are you trying to patch?
ok
resistance of my pipette tip is about 3M ohm. I did not measure the inner diameter og the tip.
I am tring to patch 293 cell line. I meet someone also have similar problem when patching the 293 cell line.
Internal Pipette solution
mM Compound
110 K-gluconate
20 KCl
1 MgCl2.6H2O
5 EGTA
5 MgATP
10 HEPES
the extracellular solution is standard HBSS solution
hoping you can help me. this make me very bad.