The epoxy-tannic-modified crosslinked chitosan matrix with a selectively adsorptive activity towards charged proteins

Chitosan-based matrices have been proposed for the design of absorbents with target-selective activity, because they are easily modifiable, are cationic polyelectrolytes, and can be regenerated. In this study, chitosan monomers were folded into special three-dimensional structures by crosslinking them with epichlorohydrin and tannic acid. The introduction of active and charged groups such as epoxy and phenolic hydroxyl and synergistic effects among these groups produce chitosan matrices with differing abilities to adsorb proteins such as bovine serum albumin, ovalbumin, myoglobin, and lysozyme in an acidic environment. The adsorptive efficiency of proteins was evaluated via liquid chromatography. Bovine serum albumin and myoglobin were progressively adsorbed while ovalbumin was bound due to strong affinity and lysozyme was saturated in the initial stage. The protein selectivity was primarily dependent on molecular weight, molecular size, isoelectric point, and coulombic attraction. The study illustrated varying effectiveness of charged protein adsorption as well as different adsorption profiles. [Display omitted] •Epichlorohydrin, tannic acid, and bentonite are used as linkers and fillers.•Bentonite facilitates the arrangement between heterocharges in polymeric interfaces.•Amino, epoxy, and phenolic hydroxyl groups are involved in adsorption of proteins.•Coulombic attraction between polymers and proteins influences protein selectivity.•Molecular weight, size, and isoelectric point of proteins impact the selectivity.