Multi-layer dextran-decorated poly(glycidyl methacrylate)-co-divinyl benzene copolymer matrices enabling efficient protein chromatographic separation

A strategy to prepare natural polysaccharide-decorated pGMA-DVB by grafting dextran groups was proposed for the development of efficient protein chromatographic separation. Prepared pGMA-DVB microspheres were covalently decorated with dextran through a three-step scheme. Firstly, residual vinyl groups on polymer particles were converted to epoxy groups. Secondly, one layer of dextran was covalently coupled on the microspheres by reacting with epoxy groups in solvent. Thirdly, multi-layer dextran was grafted to microspheres in alkali aqueous solutions. The dextran-decorated microspheres named pGMA-DVB-Dextran were characterized by Fourier transform infrared spectra, scanning electron microscope, atomic force microscopy, laser scanning confocal microscope, and protein adsorption experiment. Consequently, compared to several commercial hydrophilic beads such as Sepharose® 4FF and POROS® OH, the permeability and hydrophilicity of the modified microspheres were improved, the contact angle decreased from 153° to 0°, and nonspecific adsorption of proteins was decreased to zero. The covalently drafting amount of dextran onto pGMA-DVB was increased to 241.86 mg/mL microspheres, and the dextran layers were stable after washing with 1 M HCL/NaOH solutions. Functional ligands such as Protein A or DEAE coupled to pGMA-DVB-Dextran can be conveniently used to separation model protein, IgG or BSA, with > 99.5% recovery yield and high dynamic binding capacity, respectively.