Adsorption of albumin by gold nanoparticles: Equilibrium and thermodynamics studies

In this research, bovine serum albumin (BSA) experiment was carried out and then the produced BSA was used to investigate the adsorption behavior of BSA from aqueous solutions through UV–Vis spectroscopy. The changes of parameters such as contact time, pH, BSA initial concentration and temperature were tested and investigated by several adsorption experiments. The equilibrium adsorption data were described as well and fitted better by the Freundlich adsorption isotherm than the four linear Langmuir models at all studied temperatures and pHs. Moreover, surface structural change was studied for the presence of BSA and gold nanoparticles (GNPs) before and after the experiment by FT-IR spectroscopy. The maximum adsorption capacity of BSA adsorbed by GNPs was 109.54 mg/g and equilibrium constant was 0.0051 calculated by the Langmuir (four type) model at 298 K and pH = 8.6. The thermodynamic parameters implied that the adsorption processes were spontaneous and exothermic. The kinetic data indicate that the adsorption fits as well as with the pseudo first-order kinetic model.