Showing papers by "Willem Norde published in 1983"

The adsorption of Human plasma albumin on solid surfaces, with special attention to the kinetic aspects

Abstract: The adsorption of human plasma albumin, labeled with iodine-125, was studied under various conditions of sorbent hydrophobicity and charge on the sorbent and the protein. The adsorption on a hydrophobic, siliconized, glass surface was shown to be higher than on a hydrophilic glass surface. The influence of charge-charge interactions was investigated by performing the experiments at pH 4.0 (positively charged albumin) and at pH 7.4 (negatively charged albumin) and by using positively and negatively charged polystyrene surfaces. The rate of adsorption seems to be controlled by the diffusion of the protein from the solution toward the sorbent surface, unless both the albumin and the surface are negatively charged. Under those conditions the albumin molecules have to overcome an energy barrier before they are deposited. In some cases fast initial adsorption is followed by desorption of a fraction of the albumin molecules. This phenomenon seems to be related to the relative rates of deposition and of structural rearrangements in the adsorbed protein molecules.