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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.

Amorphous titania was modified with boric acid, and the resulting material was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction and X-ray photoelectron spectrometry. The new material, in contrast to conventional boronate affinity materials containing boronic acid ligands, bears boric acid groups. It is shown to exhibit high specificity for glycoproteins, and this was applied to design a method for solid phase extraction of glycoproteins as shown for ribonuclease B, horse radish peroxidase and ovalbumin. Glycoproteins were captured under slightly alkaline environment and released in acidic solutions. The glycoproteins extracted were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The binding capacities for ribonuclease B, horse radish peroxidase and ovalbumin typically are 9.3, 26.0 and 53.0 mg ∙ g -1 , respectively. The method was successfully applied to the selective enrichment of ovalbumin from egg white. Graphical abstract Schematic presentation of the capture of glycoproteins by amorphous titania modified with boric acid.

A paper-based chemiluminescence (CL) immunodevice is described for sensitive determination of the carcinoembryonic antigen (CEA). Capture antibody (Ab1) was first immobilized on the paper-based chip after plasma treatment of the paper surface. Next, carbon nanospheres functionalized with horse radish peroxidase (HRP) were attached as a signal antibody label. Strongly enhanced CL was achieved from the HRP catalyzed luminol/H 2 O 2 CL system when using a sandwich immunoassay format. CEA can be quantified with a lower detection limit of 3 pg·mL -1 . The method displays an almost 10-fold increased sensitivity in comparison to a commercial Ab2-HRP based kit. Conceivably, this sensitive method may also be extended by designing sensitive assays for other biomarkers of interest in point-of-care diagnostics. Graphical abstract Schematic of a paper-based chemiluminescence (CL) immunodevice for the determination of the carcinoembryonic antigen (CEA) by applying a multi-enzyme carbon nanosphere signal enhancement strategy.