Varying the concentration of one of a mixture of all 3 peptides alters platelet adhesion and thrombus formation under flow conditions. The relative coating concentrations of the different peptide types were altered to investigate the effect of different levels of receptor-ligand engagement on platelet deposition and thrombus formation, with 100 μg/mL as the control concentration of each peptide in the mixture. (A-D) The indicated component of the mixture was serially diluted with inert GPP₁₀; then surfaces were prepared as described. (E-H) The concentration of a given peptide was increased from 100 μg/mL to 800 μg/mL in a mixture with 100 μg/mL each of the other peptide types. The resulting peptide substrate was perfused for 5 minutes with DiOC₆-labeled whole blood at a shear rate of 1000s⁻¹. (A,E) Surface coverage (%). (B,F) Mean thrombus height (μm). (C,G) ZV₅₀ (μm). (D,H) Representative images showing thrombus deposition on peptide substrates deficient in the indicated peptide.