[Study on adsorption of human serum protein to biomaterials]

In our study of the interaction between dental implant materials and human serum proteins, a simple column chromatographic method to measure extraction of proteins by the biomaterials was developed. The method allows for subsequent analysis of the absorped proteins by two dimensional microelectrophoresis. A system to measure dyestained proteins on two-dimensional polyacrylamide gels employing a television camera for data acquisition and a micro computer for data analysis is described. It can be seen that elution from the hydroxyapatite columns are qualitatively similar, more protein eluting at 0.1 M phosphate. Less protein was adsorbed by the 1,250 degrees C and 1,400 degrees C hydroxyapatite ceramics, and equal amounts were eluted with 0.01 M and 0.1 M phosphate solutions. The 0.1 M phosphate eluates were subsequently analyzed by two-dimensional electrophoresis. The proteins adsorbed band eluted from the biomaterials, are estimated to be albumin, pl 4.7-4.9; transferin, pl 5.9 and IgG, pl 5.8-7.3. pl's were obtained from literature and tentative identifications made by comparison with the patterns of reference serum. The protein pattern from each biomaterial was reproducible. Albumin, IgG and transferin were obtained from non-treated hydroxyapatite. Different patterns were observed with eluates of 1,250 degrees C and 1,450 degrees C hydroxyapatite ceramics. The large spot, tentatively identified as albumin and a small amount of IgG, were the only proteins seen. We conclude that hydroxyapatite and hydroxyapatite ceramics can adsorbed of human serum protein. Selective adsorption of protein may occur a structure change of the material surface activated by sintered temperature.