Patch Clamp: Noise after making giga seal

8 posts / 0 new
Last post
fai
fai's picture
Patch Clamp: Noise after making giga seal

I have a noise problem during the patch clamp reccording although there is no noise befor formation of  giga seal. I have also add drift chamber in the suction tube and both recording and ground electrode were chlorinated. please tell me the solution.

The FFM
The FFM's picture
it is difficult to diagnose

it is difficult to diagnose without seeing the signal
is there any way you could upload a picture of the seal test before and after you get the giga seal?
What is the frequency of the noise?
Also what cell type are you patching? 
What channels are they expressing? 
and what is the holding potential you are using?

fai
fai's picture
I am working on hippocampal

I am working on hippocampal cultured neurons and screen out some Anti epileptic drugs on Sodium channel.
the base line after giga seal was wavy (see the attechment)
holding potential was kept at RMP of cell recorded in the current clamp mode at  0 pA. it was nearly -40 to -50mV

The FFM
The FFM's picture
It looks like you have a

It looks like you have a shielding issue when you are in whole cell mode because the frequency of those Oscillations is 50Hz (1 every 20ms).
You are going to have to check that everything is properly grounded (earthed) on your rig.  Also you may wish to consider getting a device like a Hum-Bug 50/60 Hz noise eliminator (www.quest-sci.com/pr02.htm  :vendors include - www.braintreesci.com/Products/HUMBUG.asp  or www.autom8.com/hum_bug.html) to help remove the  noise.  These work much better than the traditional notch filters.
 
 

fai
fai's picture
I have solved my noise

I have solved my noise problem by adding agar bridge in the ground electrode.
Now i  have a flactuation in the giga seal resistance it is not stable at some point.
it very between 600 MO to 1.5 GO. whats this?
please tell me all posible solution.

The FFM
The FFM's picture
check the plastic pipette

check the plastic pipette holder for cracks and the rubber seals inside for wear and tear.  Also check any juntions in the tube which applied the suction.

MarrowMatters
MarrowMatters's picture
fai said "I am working on

fai said "I am working on hippocampal cultured neurons and screen out some Anti epileptic drugs on Sodium channel.  the base line after giga seal was wavy "

TheFFM said "consider getting a device like a Hum-Bug 50/60 Hz noise eliminator (www .quest-sci.com/pr02.htm ... to help remove the  noise"

I found the link posted for the humbug outdated.  I thought id post a new url.  
www.quest-sci.com 
www.quest-sci.com/files/scan0001.jpg . 

The FFM
The FFM's picture
 Thanks for the update!

 Thanks for the update!