Multichannel Systems MEA-System Manual - Manual (Page 21)

Appendix
21
4.3 Artifacts caused by Perfusion
You observe artifacts or an increased noise level after you started the perfusion.
Possible causes:
? The artifacts correlate with an oscillation of the liquid level. The oscillation will cause the artifacts,
and also mechanically stress the biological sample.
 Use a bevelled tip for the perfusion in- and outlet. If the tip of the perfusion outlet has a blunt
end, there will be no continuous liquid flow, but instead, the following can be observed:
The liquid level will rise until it reaches the blunt tip; a discrete volume of liquid will be aspirated
in a short moment; the liquid level will rise again, and so on, leading to an oscillation. The tip
should be cut in an angle of about 45 °. You can also use commercially available metal needles
with a bevelled tip.
? The perfusion is not appropriately grounded.
 Connect the perfusion line to the ground of the amplifier / setup. You should consider using
a metal cannula that can directly be connected to ground for the perfusion inlet and outlet.
You could also insert a metal wire that is connected to ground into the tubing.
? The aspiration pump is oscillating.
 MCS recommends the use of the peristaltic perfusion system PPS2 for an open perfusion system.
The more rollers the pump head has, the lower are the oscillations of the fluid flow. For a
continuous perfusion in a closed system, you can also use an infusion-withdrawal syringe pump.