Ligand amount

Hi!
Do anyone of you what`s the amount of free NH2-groups after surface activation with EDC/NHS on the chip surface? Or is it possible to calculate this?
Thanks!
Pharmchem

I can't give you the answer but for a start some values.

Dextran used on the chip: Mr = 50.000 Da
Total dextran on the chip: 1-3 ng/mm2
Height of dextran: 100 nm
Stokes radius of Dextran 50.000 = 4.95 nm

dextran is build of glucose residues linked by 1,6 bonds:
alpha-D-1,6 glucose linked glucan.

1 residue: Mr = 162 Da
1 carboxyl per residue

Binding capacity of the dextran matrix in concentration volume: 50 ng/mm3

Sprboard

Hi,

i am not sure, if you mean free carboxylic groups on the chip after activation. If so, i depends on the conditions of your activation. An answer u possibly find here:
Analytical Biochemistry 198, 268-277 (1991)

regards,
Jens