Sequential protein adsorption and thrombus deposition on polymeric biomaterials

Abstract A canine ex vivo arteriovenous shunt model was employed to investigate the effect of preadsorbed blood plasma proteins upon platelet deposition. Albumin and fibrinogen were singly, sequentially, or competitively adsorbed on polyvinyl chloride (PVC), polyethylene (PE), and crosslinked silicone rubber (SR) tubing. Results indicate that platelet deposition and thrombus formation are strongly influenced by the sequence of protein adsorption. The platelet response appears to be determined by the first protein which is preadsorbed to the surface. This response does not appear to correlate well with the total amount of preadsorbed albumin or fibrinogen. To clarify how the sequence of protein adsorption affected the blood response, the sequential adsorption phenomenon was studied using 125I-labeled proteins, Fourier transform infrared spectroscopy, and immunogold particle labeling techniques. It was observed that in the sequential adsorption of albumin followed by fibrinogen, there is a linear correlation between the surface concentrations of fibrinogen and albumin on PVC. On PE and SR, a linear correlation between the fibrinogen and albumin concentrations exists only below a monolayer coverage of albumin. On SR, the initial fibrinogen adsorption rate correlates linearly with the submonolayer concentration of adsorbed albumin. When fibrinogen adsorption is followed by albumin adsorption, no linear correlations in protein adsorption are observed.