(A) SPR sensogram for the association and disassociation of the bare VEGF (black line, 1), the mixture of VEGF and unmodified alginate (blue line, 2), and the complex of VEGF and alginate sulfates (DSsulfates = 13.3%) (red line, 3) to the VEGFR-2 immobilized on the lipid bilayer surface built on a gold chip. (B) Association (ka) and dissociation rates (kd) were quantified by fitting the RU response curve obtained in (A), to the Langmuir adsorption model. The binding affinity constant (KA) between VEGF and the VEGFR-2 was quantified by dividing ka by kd.