Identification of rapid changes at plasma–solid interfaces

Abstract Recording ellipsometers and surface film balance, breath patterns, and ferric oxide powder “staining” were used to observe adsorption of normal plasma constituents onto metal oxide, silicon oxide, and polymer surfaces. Adsorbed proteins could be identified by their ability to adsorb matter from corresponding antihuman sera. Data indicate that oxidized silicon crystal surfaces adsorbed fibrinogen out of plasmas within 2 sec; within 20 sec, these films lost their ability to attract antifibrinogen and were later partially removed if intact factor XII was present in the solution. One aminated nonheparinized polymer formed films that adsorbed large amounts of fibrinogen and some gamma globulins out of plasma in the ellipsometer, and platelets out of platelet‐rich plasma, as well as ferric oxide out of aqueous suspension. After taking up heparin, these polymer films appeared able to adsorb only small amounts of protein or oxide, and no detectable amounts of fibrinogen or platelets. On another aminated polymer, heparin seemed without effect. Interaction of metal surfaces with plasma may be complicated by oxidation.