Synergistic effect of organic-inorganic hybrid monomer and polyhedral oligomeric silsesquioxanes in a boronate affinity monolithic capillary/chip for enrichment of glycoproteins.

A boronate affinity monolith with improved affinity and selectivity for glycoproteins was prepared starting from two monomers. The first is 3-aminopropyltriethoxysilane-methacrylic acid (APTES-MAA), and the other is a polyhedral oligomeric silsesquioxane (POSS) monomer. In the next step, 3-(acrylamido)benzeneboronic acid was adopted as boronate affinity ligand, and ethylene glycol dimethacrylate as the crosslinker, and iso-propanol and octanol as binary porogens. The synergistic effect of APTES-MAA and POSS warrants good affinity and selectivity for glycoproteins, which results in a number of attractive features including (a) a wide operation pH range (from 5 to 8); (b) higher enrichment factors ranging from 19.3 to 20.6; (c) greater recoveries of glycoproteins between 95.8 and 107.1%; (d) lower relative standard deviations of ≤4.2%. Compared to the corresponding APTES-MAA/POSS-free monolith, the new boronate material had 1.7-fold increased glycoprotein recovery from complex samples. Glycoproteins in 500-fold diluted serum samples can be enriched by the boronate monolith. Graphical abstractSchematic representation of the preparation of 3-aminopropyltriethoxysilane-methacrylic acid/polyhedral oligomeric silsesquioxanes boronate affinity monolith. This sorbent exhibits high selectivity and wide pH operation range for capturing glycopeptides.