Protein adsorption and zeta potentials of a biphasic calcium phosphate ceramic under various conditions

An investigation on the relationship between protein adsorption and zeta potentials of a biphasic calcium phosphate (BCP) ceramic was carried out. Zeta potentials of the BCP ceramic particles were measured at various aqueous solutions. Bovine serum album (BSA) and its competitive adsorption with lysozyme (LSZ) on BCP were investigated using conventional protein adsorption and polyacrylamide gel electrophoresis (PAGE) methods. The results showed that zeta potential and the amount of adsorbed BSA were both influenced by pH, ionic strength, Ca2+ and PO4(3-) concentrations in the buffers. The variation tendencies of BSA adsorption were consistent with that of zeta potentials to some extent. The co-adsorption of BSA and LSZ on BCP was confirmed by the PAGE gel pattern. The semi-quantitative analysis for the detected protein bands proved that LSZ had higher affinity for BCP than BSA and would preferentially bind to the surface. Electrostatic interaction played an important role in protein adsorption on the surface of the BCP ceramic particles.