PROTEIN-REJECTING ABILITY OF SURFACE-BOUND DEXTRAN IN END-ON AND SIDE-ON CONFIGURATIONS - COMPARISON TO PEG

There is much interest in attaching, polyethylene glycol (PEG) and oth er hydrophilic, neutral polymers to surfaces to reduce the extent of p rotein and cell adsorption. Interestingly, these same surface-bound po lymers are effective in masking surface charge and reducing electrokin etic effects such as particle electrophoretic mobility, streaming pote ntial, and electroosmosis. It is apparent that similar molecular prope rties are responsible for both protein and cell rejection and reductio n of electrokinetic effects. In this work we compared the fibrinogen-r ejecting ability and the effect on electrophoretic mobility of three p olymer coatings bound to polystyrene. The three polymers were side-bou nd dextran, end-bound dextran, and end-bound PEG. The results of these measurements were used to elucidate the importance of polymer packing density and polymer layer thickness on protein adsorption and reducti on of electrokinetic effects. Protein adsorption appears not to be sen sitive to polymer layer thickness or the presence of dilute polymer ta ils in a surface coating, while electrokinetic effects are. Protein ad sorption is, however, very sensitive to the availability of exposed su rface. Finally, the unique effectiveness of PEG is apparent in this re search as in previous studies. (C) 1995 John Wiley & Sons, Inc.