Biorecognizable polymers: Structure‐properties relationship

The biocompatibility of polymers depends on their chemical composition, as well as physical and physico-chemical structure. However, biocompatibility is not an intrinsic polymer property since it relates to a particular localization of the polymer in the living organism. Any foreign macromolecule may be recognized by the living organism as “non-self”. The degree of recognition can be altered by modification of the structure of macromolecules or biomaterial surfaces. Modification of biomacromolecules (e.g., enzymes1) or biomaterial surfaces with hydrophilic polymers, e.g., poly(ethylene oxide2) or other semitelechelic hydrophilic macromolecules3 has been shown to minimize biorecognition. On the other hand, to achieve specific recognition by cell receptors and/or antigens, complementary structures have to be incorporated as a part of the polymer structure4, 5. The biorecognition of fluorescently labeled N-(2-hydroxypropyl)-methacrylamide copolymers containing side-chains terminated in acylated galactosamine by Hep G2 cells on the cellular and subcellular levels can be visualized by confocal fluorescence microscopy. The recognition of modified water soluble macromolecules strongly depends on their solution properties6. Incorporation of stimuli sensitive moieties into copolymer side-chains permits to control recognition by external stimuli, e.g., irradiation7, 8, resulting in the change of the copolymer conformation. On the other hand, the biorecognition of unsoluble (crosslinked) copolymers depends mainly on their surface structure. The rationale for the structure modification of synthetic copolymers to regulate biorecognition will be reviewed. The principles will be described for the interaction of synthetic polymers with enzymes9, cell surface receptors and/or antigens10, 11, lectins of the gastrointestinal tract12, 13, and immobilized lectins14.