Capture level decrease

Hi

We are facing a serious problem in which when ever we are performing a kinetic experiment by a capture method the capture level is drastically falling down from cycle to cycle.

Here we are immobilizing anti-Histidine antibody (50ug/100uL) on CM5 chip using specify contact time (420 Seconds) which results in 10 to 12 thousand Ru final response.
Capture used is FcRn.
IgG antibody as the analyte.
Regeneration is 10mM Glycine pH-1.5.
The run includes 6 dilutions in which four samples are run in one run i.e., in total 28 injections. The capture level is not remaining consistent from the first injection to the last injection.
Please refer the file attached for a better understanding.

Please consider.

Thanks
Best regards
Anil

Hi Anil,

Welcome to the forum. The attached file is missing and I have some questions.
If I understand well you have a sensor chip with the following:

- CM5 - anti-HIS ab - FcRn and and IgG as analyte.

You have the anti-HIS covalently bound and it will capture a (HIS-)FcRn?

My first guess is that the regeneration solution is too harsh for the system. You could try the systems described at www.sprpages.nl/kinetics-2/regeneration
to find a better solution.

Kind regards

Arnoud