The rapid development of biotechnology requires more and more biomolecules of large molecule size such as protein and plasmid DNA to be purified. Up to now, liquid chromatography (LC) is an important tool and a necessary step for the separation and purification of biological macromolecules. Packing materials such as poly(styrene–divinylbenzene) (PS) microspheres have been used to improve the separation of proteins, but slow mass transfer rate is the factor that restricts their application.

Researchers with China University of Petroleum (East China) and Institute of Process Engineering (IPE) have attempted to hydrophilize the gigaporous PS microspheres using natural saccharide and chemical coupling.

In their experiments, gigaporous poly (styrene–divinylbenzene) (PS) microspheres were hydrophilically modified with natural saccharide to minimize their nonspecific adsorption to proteins. The microspheres were chloroacetylated through Friedel–Crafts acetylation with chloroacetyl chloride, and then coupled with diacetone-D-glucose (DAGlu) through the Williamson reaction, and the protecting groups were removed on DAGlu.

Results showed that the PS microspheres were successfully coupled with DAGlu and that the gigaporous structure was well maintained. After removal of the protecting groups on DAGlu, the hydrophilicity and biocompatibility of PS microspheres were greatly enhanced, nonspecific adsorption of proteins on PS microspheres was greatly reduced. The high surface density of hydroxyl groups on Glu-PS microspheres surface make it easy to derivatize the spheres by classical methods.

Besides, the mechanical stability and permeability of the medium was evaluated through the effect of flow rate on the back pressure of column, and the mobile phase was high-purity water. The surface of hydrophilicity was evaluated by gravimetric analysis. Result indicated that the Glu-PS column had low backpressure, good permeability and mechanical stability.

This study showed how to prepare a hydrophilic chromatographic support for different types of chromatography such as ion-exchange or affinity chromatography since the glucose coatings can easily be derivatized by classical methods. With further derivatization, the coated gigaporous microspheres should potentially play important roles in high-speed preparative protein chromatography.

The paper was published in Reactive and Functional Polymers.