THE INTERACTION OF BLOOD PROTEINS WITH ALPHA-ALUMINA

The use of alumina (alpha-Al2O3) as a material for cardiovascular appl ications was investigated on the basis of protein adsorption and throm bus formation on the material. The adsorption of I-125-labelled albumi n and fibrinogen from phosphate buffered saline (pH 7.35, 0.100 M NaCl , 8.66 mM KH2PO4 and 41 mM Na2HPO4) solution on ceramic discs of alumi na was studied. Both albumin and fibrinogen presented affinity for cer amic surfaces, with adsorptions of 1.47 +/- 0.06 ng/cm(2) and 0.198 +/ - 0.01 ng/cm(2), respectively. Scanning electron micrographs of the al pha-Al2O3 surfaces after contact of the discs with whole human blood s howed a thrombogenic behavior of alumina alpha. These results indicate a hemoincompatible property. Although critical surface tension (gamma (C): 21.8 dynes/cm) of the disc surfaces determined by contact angle t echnique of sessile drops indicates that alumina alpha is a biocompati ble material, by this criterion, the data reported here indicate that alpha-Al2O3 cannot be used for cardiovascular applications.