I have a doubt. I have biotynilated antibody that I will capture over a streptavidin chip. I dont have any other biotnylated antibody that I could use for the reference spot. What would you recommend in this case? a bare Streptavidin spot? Activate and deactivate the chip? Covalenty immobilize an antibody on the surface?
I am using now a streptavidin chip and use as reference just the native surface with streptavidin on it. There is no background binding so this is ok.
Activating / deactivating is not usefull because you don't do that with the other surface. Actually it is immobilized with streptavidin. Probably you will introduce some modifiaction you do not want with an extra activation.
It is maybe better to saturate the reference surface with biotin.
I just saw what you mentioned, Arnout. On an activated-deactivated spot I get more background than in SAv-coated spot. I have D-biotin (Sigma) for blocking the SAv, does anyone know what concentration should I use?