Biocompatibility of alumina ceramic and polyethylene as materials for pivot bearings of a centrifugal blood pump

The double pivot bearings in the Gyro C1E3 centrifugal blood pump incorporate a high-purity alumina (A1₂O₃) ceramic and an ultra-high- molecular-weight polyethylene (UHMWPE). This centrifugal pump has been developed as a completely sealless pump for long-term usage. The combination of A1₂O₃ and UHMWPE are the materials of choice for the acetabular bearing in artificial joints, which have proven to be clinically reliable for over 10 years. Previous studies have examined the biocompatibility of Al₂O₃ and UHMWPE as bulky implant materials. The present study investigated this material as a blood-contacting material using a standard assessment in vitro and in vivo analysis. The examined items were systemic toxicity, sensitization (guinea pig maximization test), cytotoxicity (elution test), mutagenicity (Ames test), direct contact hemolysis, and thrombogenicity. The studies were performed according to the United States Pharmacopoeia and published previous studies. The samples of both Al₂O₃ and UHMWPE demonstrated no differences from the negative controls in all tests. These findings indicate that both Al₂O₃ and UHMWPE are biocompatible materials for double-pivot bearings in the centrifugal blood pump.