Adsorption of bovine serum albumin onto hydroxyapatite.
The adsorption of bovine serum albumin (BSA) onto hydroxyapatite (HA) has been studied as a function of protein concentration, pH and ionic strength. Isotherm data (adsorption being a reversible process) have been analysed using the Langmuir model, the adsorption parameters AT (maximum amount of protein adsorbed, mg m-2) and K (affinity constant, L g-1) being calculated for each solution condition (except NaF). For the pH dependence of adsorption, both AT and K increase with decreasing pH, indicating that both electrostatic and hydration effects are important. For the ionic strength dependence, increasing NaCI concentrations result in a slight increase in AT, but K decreases. With increasing CaCI2 concentrations the AT and K values increase, the opposite being true for increasing concentrations of Na2HPO4. NaF both enhances and inhibits adsorption depending on the concentration. Possible reasons for these results are discussed.
Wassell
D T
DT
Department of Basic Dental Science, Cardiff Dental School, University of Wales College of Medicine, Health Park, UK.
Hall
R C
RC
Embery
G
G
D000327:Adsorption; D017886:Durapatite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009994:Osmolar Concentration; D012492:Salts / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000493:pharmacokinetics; D012996:Solutions
D012492:Salts; D012996:Solutions; D012710:Serum Albumin, Bovine; D017886:Durapatite