Hydrophobically driven attachments of synthetic polymers onto surfaces of biological interest: lipid bilayers and globular proteins.

This paper gives a brief overview of the consequences of associations between amphiphilic water-soluble polymers and small colloidal particles of biological interest: proteins and vesicles. Typical structures of water-soluble synthetic polymers containing hydrophobic groups are presented. The segregation between polar and apolar units in these polymers induces self-organisation in micro-domains despite the lack of specific primary structure. In the presence of other amphiphilic particles like proteins and vesicles, mixed assemblies are formed. Examples of polymer associations with vesicles or globular proteins, mainly focused on the acrylic derivatives, bring out common features in these mixtures. When the size of the polymer is of the same order of magnitude as that of the particle, adsorption of polymer chains creates a protective layer around each individual particle. Depending on the hydrophobicity of the partners, the association can stabilise the dispersion of unmodified particles or induce structural changes (membrane disruption, leakage). When small particles are added to solutions of long polymers, multimolecular complexation occurs. In this case, the size of the resulting aggregates depends on the concentrations. It goes from the size of one polymer molecule up to formally infinity as revealed by gelation. The identification of non-specific association modes between biological nanoparticles and macromolecules might be revealed by the general behaviour of these synthetic mixed systems.