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[26] Methods for studying protein adsorption

1999; Academic Press; Linguagem: Inglês

10.1016/s0076-6879(99)09028-x

1557-7988

Vladimir Hlady, Jos Buijs, Herbert P. Jennissen,

Hydrogels: synthesis, properties, applications

Proteins are interfacially active molecules; this is easily demonstrated by the spontaneous accumulation of proteins at interfaces. Protein is an amphoteric polyelectrolyte. Its amino acids have different characteristics; some are apolar and like to be buried inside the protein globule, whereas others are polar and charged and are often found on the outside protein surface. A strong, long-ranged electrostatic attraction between a charged adsorbent and oppositely charged amino acid side chains will lead to a significant free energy change favoring the adsorption process. In other cases, the interfacial activity of the protein may be driven by its marginal structural stability. The compactness of the native structure of the protein is because of the optimal amount of apolar amino acid residues. In order to completely characterize and predict protein adsorption, one would like to have a quantitative description of adsorption. This description is typically obtained by measuring the adsorption isotherm, adsorption and desorption kinetics, conformation of adsorbed proteins, number and character of protein segments in contact with the surface, and other physical parameters related to the adsorbed protein layer, such as layer thickness and refractive index. This chapter describes a selected set of techniques and protocols that provides the answers about the mechanism of protein adsorption onto and desorption from surfaces.