Carbohydrate decoration of microporous polypropylene membranes for lectin affinity adsorption: comparison of mono- and disaccharides

Abstract Carbohydrates (saccharides) are ubiquitous on the extracellular surface of living cells and mediate a myriad of biological recognition and signaling processes. Carbohydrate decoration of polymer surfaces with covalent attachment of saccharides offers a new realm of opportunities to mimic cellular events such as protein recognition and binding. We describe the carbohydrate decoration (surface glycosylation) of poly(2-hydroxyethyl methacrylate)-grafted microporous polypropylene membranes (poly(HEMA)- g -MPPMs) with mono- and disaccharides. Galactose, lactose, glucose, and maltose were covalently attached on the surfaces of poly(HEMA)- g -MPPMs and were compared in detail. The process was verified by solid state 13 C NMR spectra. Membranes with high binding degree ( BD ) of saccharide ligands on the surfaces were facilely prepared from poly(HEMA)- g -MPPMs with high grafting degree ( GD ) of poly(HEMA). For poly(HEMA)- g -MPPM with the same GD of poly(HEMA), the BD of disaccharides is lower than that of monosaccharides and the disaccharide-decorated MPPMs are more hydrophilic than the monosaccharide-decorated ones. The carbohydrate-decorated MPPMs prepared from galactose, lactose, glucose, and maltose (denoted as MPPM-Gal, MPPM-Lac, MPPM-Glc and MPPM-Mal, respectively) recognize and adsorb specifically one of the two lectins, concanavalin A (Con A) and peanut agglutinin (PNA). As the BD of saccharide increases, the “glycoside cluster effect” plays a primary role in lectin adsorption. MPPM-Lac has enhanced affinity to PNA as compared with MPPM-Gal having similar BD of saccharide., on the other hand, MPPM-Mal shows no enhanced affinity to Con A in comparison with MPPM-Glc as the BD of saccharide is above 0.9 μmol/cm 2 , where the “glycoside cluster effect” occurs.