I am very new to Biacore and am using a Biacore2000 to study Protein Protein Interaction. For the past 2 runs, i keep getting this THICK line in the sensogram and then my CM5 chip becomes non-responsive.
can anyone tell me what might be causing this and how i can circumvent such ? I think i already lost 1 CM5 chip.
thank you so much for your help in advance.
The thick line indicates that the curve is outside the dynamic range of the sensor.
This can have several reasons:
1) air in the flow system
2) high refractiv index solutions like high salt, glycerol or DMSO
3) misalignment of the sensor chip to the detector.
In the top figure it is high salt (1 M ethanolamine i presume).
The bottom figure I suspect some problems with the alignment.
If the problems arise after one or two runs I suspect that something in your sample is blocking the channels or depositing on the sensor surface.
When you take out the chip and look at the gold surface. What do you see?
If there is something on the chip, that is not good. It should like almost clean. Some marks of the detector on the detector side are normal.
No dust or particles allowed.
Try cleaning the instrument and wash afterwards with water.