MEASUREMENTS OF ZETA-POTENTIALS OF PARTICULATE BIOMATERIALS IN PROTEIN-RICH HYALURONAN SOLUTION WITH CHANGES IN PH AND PROTEIN CONSTITUENTS

This study was undertaken to determine the zeta potentials of particul ate biomaterials in three types of protein-rich hyaluronan solution wi th changes in pH; a microelectrophoretic method was used. For the purp ose of determining the pH value of synovial fluid in various inflammat ory conditions, we collected synovial fluid samples from joints with o steoarthritis (OA), rheumatoid arthritis (RA), and those undergoing re visions arthroplasties. The mean values of the pH in the synovial flui d from joints with OA, RA, and revision arthroplasty were shown to be 7.9, 7.5, and 8.1, respectively. The pH-zeta potential curves obtained differed, depending on the biomaterial and the medium. Addition of ga mma-globulin to the medium reduced the absolute value of the zeta pote ntials of some of the biomaterials. The findings of this study suggest that the electrophoretic behaviors of the particulate biomaterials te sted in this study are affected by the protein constituents of and pH changes in protein-rich synovial fluid. The values we obtained will be useful as reference standards and will also aid in the study of the s urface phenomena of biomaterials. (C) 1998 John Wiley & Sons, Inc.