Changes in human serum albumin on arthroplasty frictional surfaces

We investigated changes in human serum albumin caused by friction on prosthetic materials. Changes in albumin, including thermal denaturation and shearing actions from artificial joint materials, such as the pin-on-disk combinations of CoCrMo-pin on ultra-high-molecular weight polyethylene (UHMWPE)-disk, Al2O3 on UHMWPE, Al2O3 on Al2O3, and CoCrMo on CoCrMo, were examined by measurements of the kinematic viscosity and molecular weight of the protein by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) after friction experiments with a tribometer. Examinations of the surface by fluorescent staining, optical microscopy, and atomic force microscopy showed the adsorption of albumin on worn surfaces of UHMWPE and CoCrMo alloys, but not on Al2O3. Changes in both the kinematic viscosity and molecular weight of the protein occurred on hydrophobic surfaces of UHMWPE and CoCrMo alloy in the tribological process following adsorption of human serum albumin onto those surfaces.