Figure 5.

Scatchard plots of binding of proteins with gold nanoparticles. Graph (А) is for bovine serum albumin (BSA); (B) is for Kunitz-type soybean trypsin inhibitor (STI); (C) is for recombinant streptococcal protein G (protein G); and (D) is for human immunoglobulin G (IgG). K_d⁽¹⁾ is the equilibrium dissociation constant for conjugates at protein concentrations below the saturation point, K_d⁽²⁾ is the equilibrium dissociation constant for conjugates at a protein concentration close to the saturation point. [L] is the concentration of free protein, and RL is the number of protein molecules bound to a single gold nanoparticle.