noise caused by vacum pump

Hi,

Recently I start to use a 60-channel USB-MEA-system. I plan to record from whole-mount retina with a standard 200/30 um MEA. I am now setting up a perfusion system for the MEA rig, using gravity to feed the recording chamber and a vacum pump to suck the solution out from the chamber. I found that the vibration of the solution (and/or air) caused by the vacum always induce noises in quite a few numbers of channels, especially those located close to where I place the suction end of the vacum.

If I weaken the vacum, the noises will be reduced (just reduced, still exist in 2-4 channels, not completely gone), but I am afraid this is risky: it might result in spilling over of the solution. If I maximize the vacum, then nearly in all 60 channels I will see huge noises.

Acutally I am a little confused - In my old lab when I was doing MEA recording (an old MEA-system, not USB), I also used vacum (not a pump but a system built in the building) but rarely had such problems. I am wondering if my current problem is caused by a unsuitable vacum pump. Could you please recommand a vacum pump (company, Cat No.)to me, or you have some other suggestions?

Thanks a lot!

sjweng

Dear Sjweng,
usually any vacuum pump will do, many people use a cheap aquarium pump. Please see the chapter about perfusion in the acute slice application note for tips how to get a stable, noise free perfusion (http://www.multichannelsystems.com/sites/multichannelsystems.com/files/documents/applications/MEA_ApplicationNote_Hippocampus_Acute.zip).

Best regards Frank MCS