Preparation, Protein Adsorption and Blood Compatibility of Polyelectrolyte Multilayers with Different Surface Properties

Poly(styrene sulfonate)/poly( allylamine hydrochloride) multilayers were assembled on silicone wafers via the technique of layer-by-layer assembly. Their surfaces were further modified either physically or chemically with bovine serum albumin (BSA), hepanin and polyethylene glycol (PEG). Protein adsorption on these surfaces was investigated by quartz crystal microbalance (QCM), ellipsometry and atomic force microscopy (AFM). The dynamic adsorption process of BSA on these multilayers was monitored by QCM, revealing that the adsorption equilibrium was rapidly achieved within 3 min on the control and heparin adsorbed multilayer surfaces, and within 5-10 min on the chemically bonded BSA and PEG surfaces, but more than 80 min on the BSA physically modified surface. After adsorption of BSA or fibrinogen, all the modified multilayers became smoother due to the effect of "surface valley adsorption". Ellipsometry characterization found that the adsorbed mount of BSA, fibrinogen and plasma proteins on all the modified multilayers were smaller than that of the unmodified control multilayers. The platelet adsorption on the multi layers was analyzed by SEM, revealing that the number of the adsorbed platelets on all the modified surfaces except of the heparin modified one was significantly reduced. The prothrombin time (PT) of all the modified multilayers was prolonged compared with that of the unmodified multilayers, but there was no significant difference between all the samples.