Storing a immobilized CM5 chip

Dear friends,
Myself Charles, very very new to SPR. am using GE Biacore 3000. am mainly using for protein and small molecule interactions. i have few general queries.
#1.
After each run how should i store my CH5 chip immobilized with ligand. to preserve the activity of the ligand?

#2
what will happen to ligand when preserving the chip in 4 degree refrigeration in a dry environment?

#3
what will be the suitable way to preserve immobilized chips?

#4
Do we need to ruin prime after docking a chip which is already immobilized?
will it reduce the active ligand concentrarion in chip surface?

#5
what is the reason for negative peaks in SPR? what does it mean?

Dear Charles,

The storage conditions of an immobilized sensor chip should be determined empirically for each ligand. There is no one solution that fits all situations. However, in general, most proteins survive in isotonic solutions such as PBS, TBS of the Hepes saline buffer commonly used with SPR. For longer storage an anti-microbial agent can be added, such as 0.02% sodiumazide.

When undocking the sensor chip the liquid is removed from the system. The sensor surface is 'dry' (there is no visible liquid) but on the microscopic scale the matrix and the ligand are still surrounded by liquid. Storing a chip in a 'dry' condition at 4°C is an option which you should explore if it is compatible with your ligand. Alternatively, you can immerse, the chip in a suitable solution and store at 4°C.
If you only have to wait for the next morning you can leave the chip inside the instrument under standby flow (~5 μl/min).
When you dock a sensor chip, always do a prime. This serves two purposes: it flushes the system with buffer and rehydrates the sensor chip surface. This will not affect the surface.
Ideally, check your ligand with a known positive analyte.

For the negative curves: www.sprpages.nl/experiments/troubleshooting

I would suggest you read the SPRpages and search the forum to get more information
Or buy the SPRpages book to give yourself a head start with SPR.

Kind regards
Arnoud

Hi...a major advantage of SPR-based analysis is its ability to estimate the association and dissociation rate constants, an advancement over the traditional steady-state analysis of biomolecules.

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