Non-specific signals with biacore - (Mar/06/2006 )

Hi all,

I usually analyze an analyte and its receptor interaction by surface plasmon resonance:

1. Monoclonal Antibody (which recognizes the receptor) immobilization in both FC1 and FC2

2. Receptor immobilization in FC2

3. Analyte injection over FC1 and FC2

Always following this protocol and no problem. Now, I find non-specific signals in both FC1 and FC2 during analyte injection.

I am sure, no conditions, no buffers, no analyte conditions have changed.

Please any suggestion will be very appreciated. I am desperate. This is essential to finish my PhD.

Thanks you very much

hi,

i suppose you use CM5 chips
how many time have you regenerated it?
if you are sure that not conditions not buffer nor analyte quality have changed, the observed effect should be explained by a non-specific interaction with the dextran matrix...

Seb_

Yes, I use CM5 chips and this artifact effect is independent on how many times the chip has been regenerated.

Could the chip still be activated ? Is your ethanolamine solution used to block acitvated sites been changed or gone off ? That could explain it.

Also are you sure the flow path is changed so the receptor only goes onto flowcell 2? Have you tried using a non-specific analyte which you're sure does not bind your receptor? If you still get non-specific binding the first possibility seems likely, if not it could be the second one.

All the best,
Ceri