X-RAY PHOTOELECTRON-SPECTROSCOPY STUDIES, SURFACE-TENSION MEASUREMENTS, IMMOBILIZATION OF HUMAN SERUM-ALBUMIN, HUMAN FIBRINOGEN AND HUMAN FIBRONECTIN ONTO AMMONIA PLASMA-TREATED SURFACES OF BIOMATERIALS USEFULFOR CARDIOVASCULAR IMPLANTS AND ARTIFICIAL CORNEA IMPLANTS

XPS studies of untreated and ammonia plasma surfaces of PTFE, ePTE, Da cron, P(HEMA), PMMA, Silastic and PS were carried out. Ammonia plasma treatment caused significant changes in the surface composition. The c urve-fitting results confirmed the incorporation of nitrogen and oxyge n in the form of functional groups such as C-N, C=O, C-O, Si-N, Si-OH etc. Increases in die values of surface tension occurred. The surface tension of plasma treated surfaces varied between 44-48 erg/cm2 with t he exception of Dacron which became wettable. Enhanced immobilization of human albumin on plasma treated surfaces was achieved. When washed with 0.2% Tween in buffer, these albuminated surfaces were found to be stable compared to control samples. Increased immobilization of human fibrinogen was also observed. The ammonia plasma treated surfaces sho wed high binding properties and retention for human fibronectin. Ionic interaction between proteins solution and plasma treated surfaces may be cause of the increased attachment of these biological molecules.