Polymer-Protein Bioconjugate Materials

Abstract

The purpose of this research was to develop a synthetic bioconjugation method that could be potentially used to produce active materials for biomedical applications, such as hemoperfusion. Cross linked polyHEMA-based copolymers were used as a support, where the surface was chemically modified to introduce aldehydes and N-hydroxysuccinimide (NHS) esters to attach polypeptides. Glucose oxidase was used as an example of a biologically active material to graft to the polymer particles. Enzymatic activity analysis was utilized to evaluate activity of the immobilized glucose oxidase. Introduction of aldehyde and NHS-esters to the surface of polymer particles allowed chemical bonding of proteins to the polymer, which was confirmed by FTIR and NMR spectroscopy as well as by gravimetry and elemental analysis. Experiments with the model oligopeptides have shown that aldehydes of the polymer preferred reacting with thiols rather than with amines of the oligopeptides. Grafting of glucose oxidase was more effective to the aldehyde functionalized polymer than to the NHS-ester functionalized polymer. The latter polymeric conjugate has shown a higher activity of the immobilized enzyme despite its lower weight fraction in the material. The covalently attached biomolecule was not lost during the reaction with glucose and activity of the conjugate material lasted through 5 consecutive experiment performed with the same sample.