Fabrication of self-reinforced polymorphic cellulose nanofiber composite microspheres for highly efficient adsorption of proteins

A serious decrease in compression strength of cellulose-derived chromatography media has greatly restricted their applications, especially in protein separation. Herein, we reported a unique route to construct polymorphic cellulose nanofiber composite microspheres (PCCMs), which highlighted strong compression resistance and high specific surface area in comparison to other cellulose counterparts. The strong compression resistance of PCCMs is ascribed to the entrapment of semi-dissolved natural cellulose nanofibers (CNFs) in the cellulose network, by which the compressive strength increased by 78% after natural CNF entrapment. Meanwhile, a pre-crosslinking reaction of cellulose solution was carried out to reduce the regeneration of cellulose crystalline regions, which endowed the PCCMs with a high specific surface area of about 217.44 m2 g−1. Diethylaminoethyl chloride was applied to modify PCCMs to prepare the anion exchanger. The as-prepared DEAE/PCCMs displayed excellent adsorption capacities of 105.58 mg g−1 for bovine serum albumin and 270.78 mg g−1 for bovine hemoglobin. The dynamic adsorption of proteins was investigated in a fix-bed column, and the breakthrough curves proved the applicability of DEAE/PCCMs in practical applications.Graphical abstract