Protein conformational changes induced by adsorption onto material surfaces: an important issue for biomedical applications of material science

Abstract

Abstract. Protein adsorption on solid surfaces is a widespread phenomenon of large biological and biotechnological significance. Conformational changes are likely to accompany protein adsorption, but are difficult to evidence directly. Nevertheless they have important consequences, since the partial unfolding of protein domains can expose hitherto hidden amino acids. This remodeling of the protein surface can trigger the activation of molecular complexes such as the blood coagulation cascade or the innate immune complement system. In the case of extracellular matrix, it can also change the way cells interact with the material surfaces and result in modified cell behavior. In this review, we present direct and indirect evidences that support the view that some proteins change their conformation upon adsorption. We also show that both physical and chemical methods are needed to study the extent and kinetics of protein conformational changes. In particular, AFM techniques and cryo-electron microscopy provide useful and complementary information. We then review the chemical and topological features of both proteins and material surfaces in relation with protein adsorption. Mutating key amino acids in proteins changes their stability and this is related to material-induced conformational changes, as shown for instance with insulin. In addition, combinatorial methods should provide valuable information about peptide or antibody adsorption on well-defined material surfaces. These techniques could be combined with molecular modeling methods to decipher the rules governing conformational changes associated with protein adsorption.

Electrical and dielectric characteristics of Al/polyindole Schottky barrier diodes. II. Frequency dependence

“…The intrinsic fluorescence of tryptophan, tyrosine and to a lesser extent phenylalanine is a sensitive probe of conformational changes because the intensity and Stokes' shift of the fluorescence emission depends on the local environment of the fluorophore 42. The unfolding of human serum proteins albumin, fibrinogen and γ‐globulin were studied by measuring the intrinsic fluorescence intensity at a excitation wavelength corresponding to tryptophan or tyrosine fluorescence.…”

“…The dissolved, native fibrinogen, does not bind to the adhesion receptors of platelets. When fibrinogen adsorb on a surface and a conformational change occur, some amino acids previously hidden inside the molecule becomes exposed and able to interact with the platelet receptors 31, 42, 48, 49. Also, it is well known that platelet adhesion and spreading do not occur on an albumin‐coated surface, and that with increasing degree of albumin denaturation, platelet adhesion and activation are enhanced 49.…”

Study of protein coatings cross-linked via the free-radical mechanism on magnetic nanoparticles by the method of spectral and fluorescent probes

“…Serum albumin is one of the most important protein components of blood plasma. The preservation of the native structure of albumin upon its immobilization on the surface of nanoparticles pro vides them with hemocompatibility and hinders undes ired adsorption of other proteins [9].…”

Linear Array of Multi-Substrate Tracts for Simultaneous Assessment of Cell Adhesion, Migration, and Differentiation

“…A variety of residues can be used (e.g., sulfhydryl or amino side groups) to optimize retention of functional structure, with amine-based immobilization being perhaps the most common means for attaching proteins, since not all proteins have an exposed cysteine. Regardless of how proteins are attached to the substrate, numerous variables remain concerning the extent of native protein conformation preservation (33–35). …”