A Thermodynamic Study of Albumin Adsorption onto Some Solid Surfaces

In order to understand protein adsorption, the thermodynamic parameters were evaluated from the initial slope of the isotherms of human albumin adsorption onto glass, Biomer (a hydrophobic plyurethane), 2-600 (a hydrophilic polyurethane) and silicone surfaces. The Gibbs free energy (ΔG) values of albumin adsorption in 10 mM phosphate buffer at pH 7.35 and at 23°C were -5.24, -6.46, -4.55 and -7.21kcal/mol, respectively. These values changed in 1M NaCl-10mM phosphate to -3.75, -6.99, -4.57 and -8.21kcal/mol, respectively. There was a clear influence of salt concentration on the ΔG values of albumin adsorption on glass surfaces in the range of 0-0.5M NaCl in the phosphate buffer.