Linkage chemistries

How is carboxymethyl dextran covalently coupled to the gold surface? What crosslinking reagent is used?
jason

Hi Jason,

The dextran is linked to the gold with a SAM (self assebled monolayer).
see: www.sprpages.nl/spr-overview/sensor-chips.html

Hi. Yes, thank you but I'm looking for the specific protocol. I can link a protein to gold with DSP. 11-mercaptododecanol is commonly used as a SAM. An epoxide can be used to link the SAM to the sugar but how do I make sure the dextran preferentially binds to the SAM and does not crosslink with itself?
Thanks
jason

Mmm, I don't have a specific protocol.

Dextran has free -COOH groups at the end of the chains. My hunch would be that the internal cross-linking between the dextran is not a real issue when you use chemistries targetting the -COOH groups.
see: en.wikipedia.org/wiki/Dextran
Arnoud

Dextran must be carboxylated with bromoacetic acid right? I've found this paper so far...http://www.sciencedirect....le/pii/S0956566302000842
Another option might be to create aldehydes on the dextran and link that to hydrazide.
jason

Hi Jason, yes thats right: I use 1 M in 2 N NaOH overnight in a humidity chamber.
Be careful because the 2 N NaOH will etch (in case of Biacore chips, do not let it touch the plastic and glue!
The ref I use is:
Chatelier, R. C., et al. "A general method to recondition and reuse BIAcore sensor chips fouled with covalently immobilized protein/peptide." Analytical Biochemistry 229.1 (1995): 112-18.
Arnoud