Immobilisation Issue

Hi,

I have been trying to immobilize my His-tagged protein (ligand) on CM5 surface at concentration of 0.05mg/ml at a targeted response of 5000 RU. The run aborted with error message of pre-concentration reaction is too slow. Does it mean I need to increase the concentration of protein? If yes, can I rescue this chip to reuse with increased ligand concentration?

Thanks,
Tabassum

Hi,
Yes you can reuse the chip. Look at the sensorgram and notice what the program did. It checked the pre-concentration and cleaned the surface with NaOH and aborted. You have to replace both ligand solution and NaOH.
Now you have to notice the pre-concentration rate. There is a trade-off between pre-concentration rate and target. Too fast and you get overshoot when the target is low and too slow when your target is high. What the acceptable range is, is thus dependent on the target.
To modify the pre-concentration rate you can change the protein concentration or pH of the immobilisation buffer.
I normally have a pre-concentration between 20 (low) to 100 (high) RU/s.

kind regards
Arnoud