Hello. Has anyone seen variation in CM5 performance. Like it would have a good response on one chip and when you use a different chip it would be different? (ie. completely different sensorgram profiles). Also has anyone heard of a new CM5 chip out with better performance? Finally what is everyone's experience the lifetime of a chip. How do you know it is still good? A drop in RU's of your control. Any reply info. would be most helpful....
As far as I observed is the batch to batch variation between CM5 chips low. We use research grade chips. For the best reproducibility use the certified sensor chips.
In general the sensorgram is higly dependent on the used ligand and analyte. So when you find totally different sensorgrams first check the stability of your samples and reagent before you doubt the sensor chip or machine.
The same holds for the lifetime of a immobilized sensor chip. Every cycle of analyte binding and regeneration will change the surface and affect the lifetime. A positive control will help you monitor the validity of the surface. In addition the baseline will give you some information about the state of the surface.
I completely agree with Arnoud. From my experience in 99% of the cases the reactives are the problem. The positive control has to be run everyday before starting and if the work is intense, after every given cycles. Also if you want to compare inter-chip performace you can compare this control. Also protein batches vary 1000 times more than chip batches.