Anybody knows what the lifetime for CM5, I mean how many experiments I can run using one CM5, specially working with small molecules, mine is dead after 120 injections (30 injection/cycle) so what do you think?
You probably mean the lifetime of the ligand on the sensor chip.
It depends on the ligand. Antibodies are quite robust but some other proteins not. It also depends on the buffer and regeneration conditions used.
And the analyte: pure protein or compound (DMSO) or culture medium.
So it is hard to predict how long a ligand surface will be functional.
1) If the DMSO will affect your ligand is dependent on the nature of the ligand. With low concentrations (<2 %) this will be probably not a real issue. But you have to test each ligand for stability. If you have a positive control you can inject this every 1-15 cycles to test the ligand integrity.
2) Theoretically this is possible since the first activation of the sensor chip will not activate all the carboxyl groups of the dextran matrix. But when you try a second activation you will also modify the existing ligand on the surface....
I never have seen anyone doing this.
If sensorchip cost are an issue you can try to recondition the surface.
You should be very careful when using this procedure and make sure the chip is still firmly attached to the holder since aggressive reagents are used.
Ref: Chatelier, R. C., Gengenbach, T. R., Griesser, H. J., et al.; A general method to recondition and reuse BIAcore sensor chips fouled with covalently immobilized protein/peptide. Analytical Biochemistry (229) 1: 112-118; 1995.