Since C1 sensorchip does not have a dextran matrix, the atrraction to the surface will be minimal (or not). In addition the flat surface as a binding capacity of only 10% of a CM5 sensor chip.
You may want to activate and bind your DNA for a longer period. Standard buffer should be fine.
Why did you choose for the C1?
I want a flat chip, so without dextran layer. That's the reason I choose for C1.
With some buffers, I seem to have attraction to the surface, but nothing gets immobilized.
I eventually circumvented the problem by first immobilizing streptavidin onto a C1 chip and then I coupled biotin labeled DNA to the streptavidin. This works well, however, for future experiments, it should be nice if I was able to directly immobilize NH2 labeled DNA to the C1 chip.
I think we have done this in the past, but it took some optimizations.
We used standard buffer but added high salt concentrations in the immobilization buffers, if I remember correctly it was + 750 mM NaCl in the HBS buffer
Longer incubation times were indeed necessary, together with a high DNA concentration and reduced flow rates