Surface modification of chitosan for selective surface–protein interaction

This study evaluates the chromatographic performance of a support obtained by the reaction of a variety of ligands with di-epoxide (1,4 butanediol diglycidyl ether) activated chitosan beads. Chitosan beads 400–625 microns (μm) in diameter and with a solid contents of 4.5% were selected for this study. The activation step was optimized with respect to time, temperature, and starting epoxide concentration. Epoxide activity in the range of 600–1200 μmoles of epoxide per gram of chitosan was obtained. Epoxide activated beads were then reacted with synthetic ligands to yield a support for use in bioseparations. Ligand modified chitosan beads were observed to selectively bind human serum albumin (HSA) over human fibrinogen and human immunoglobulin. Purity of the products, obtained from a single purification step, as judged by electrophoretic analysis was estimated to be greater than 95%.