Uniform polysaccharide composite microspheres with controllable network by microporous membrane emulsification technique

High resolution has been constantly pursued in both preparative and analytical chromatography. Chromatographic media are a key factor during the entire separation process. Tailor-made chromatographic media have gained more attention because of their adjustable structure appropriate for application. Uniform polysaccharide composite microspheres were prepared with a mixture of agarose and dextran solution by membrane emulsification technique for the first time. Their pore structure was deliberately regulated by adjusting both the polysaccharide composition and the molecular weight of dextran. Compared with pure agarose microspheres, polysaccharide composite microspheres had a higher separation resolution and their separation range was controllable. By increasing agarose concentration and decreasing dextran concentration at the same time during the preparation of composite microspheres, the mean pore size increased first and then decreased later, and also the pore size distribution became narrower. By increasing the molecular weight of dextran, the pores became smaller with a narrower pore size distribution. Microspheres with a composition of 10% agarose/2% dextran T40 or 8% agarose/4% dextran T150 showed a higher separation resolution for proteins within range of low molecular weight. Furthermore, the mechanical strength of this composite microsphere was improved by adjusting its composition. Atomic force microscope (AFM) results showed that pores were distributed evenly on both the surface and the inner part of microspheres, beneficial for the passage of biomolecules. These novel uniform polysaccharide composite microspheres have great potential for high-resolution bioseparation.