The interaction of blood proteins with alpha-alumina

The use of alumina (alpha-Al2O3) as a material for cardiovascular applications was investigated on the basis of protein adsorption and thrombus formation on the material. The adsorption of 125I-labelled albumin 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 alumina was studied. Both albumin and fibrinogen presented affinity for ceramic surfaces, with adsorptions of 1.47 +/- 0.06 ng/cm2 and 0.198 +/- 0.01 ng/cm2, respectively. Scanning electron micrographs of the alpha-Al2O3 surfaces after contact of the discs with whole human blood showed 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 technique of sessile drops indicates that alumina alpha is a biocompatible material, by this criterion, the data reported here indicate that alpha-Al2O3 cannot be used for cardiovascular applications.