Specifications

Troubleshooting
23
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 a peristaltic pump 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 an infusion-withdrawal syringe pump.