Synthesis and application of novel phenylboronate affinity materials based on organic polymer particles for selective trapping of glycoproteins

Abstract

We report on synthesis concepts for the fabrication of various novel phenylboronate affinity materials based on polymethacrylate epoxy beads (Fractogel EMD Epoxy (M) 40-90 microm) and the testing of these functionalized polymer particles for selective trapping of a glycoprotein from a standard mixture containing a glycosylated and a nonglycosylated protein. Two inherently different approaches for the functionalization of the bare beads with boronate groups have been elucidated. In the first, the epoxy residues of the polymer particles were converted into reactive thiol groups which were subsequently used as anchor moieties for the immobilization of 4-vinylphenylboronic acid by radical addition or radical polymerization reaction. Three different ways for the generation of sulfhydryl groups have been examined leading to materials with distinct linker chemistries. In the second and more straightforward approach, the epoxy groups were reacted with 4-mercaptophenylboronic acid. The novel materials were thoroughly characterized by (i) quantitation of the sulfur content by elemental analysis, (ii) reactive sulfhydryls were determined in a photospectrometric assay, (iii) boron content was measured by inductively coupled plasma-atomic emission spectrometry, and (iv) the amount of reactive boronate groups was evaluated in a fast binding assay employing adenosine as test compound. A maximum concentration of 1.2 mmol boronate groups per gram dry beads could be achieved by the presented synthesis routes. Employing the novel phenylboronate affinity materials in capture and release experiments in the batch mode, a standard glycoprotein, viz. transferrin (Tf) from human serum was separated from a nonglycosylated protein, BSA. A commercial boronate affinity material based on 3-aminophenylboronic acid modified agarose gel was employed as reference material and was found to perform significantly worse compared to the herein presented novel polymethacrylate particles.

Adsorption characteristics of stevioside and rebaudioside A from aqueous solutions on 3-aminophenylboronic acid-modified poly(divinylbenzene-co-acrylic acid)

“…Since boronic acids form a covalent and reversible interaction with cis-diols in water [15], it is a little surprising that boronic acids have been widely used as affinity ligands for the separation of carbohydrates [16], glycoproteins [17,18], and nucleotides [19]. Boronic acid-containing adsorbents with good adsorption selectivity toward cis-diols are usually prepared by a copolymerization procedure or a chemical modification procedure.…”

Synthesis of boronate-silica hybrid affinity monolith via a one-pot process for specific capture of glycoproteins at neutral conditions

“…The mechanism can be explained that the boronic acid can covalently bind with cis-diols to form five-or six-membered cyclic esters in a basic aqueous media; the reversible disassociation can be performed under acidic conditions. The excellent specificity makes boronate groups potential affinity ligands for specific recognition and isolation of cis-diol-containing compounds, including catechols, nucleotides, carbohydrates, nucleosides, glycopeptides, and glycoproteins [11][12][13][14]. In addition, the moderate acidic elution condition make boronate affinity well coupled with mass spectrometry for analysis of cis-diol biomolecules in -omics [14][15][16].…”

Responsive Boronic Acid-Decorated (Co)polymers: From Glucose Sensors to Autonomous Drug Delivery

“…Similar functionalized materials were designed by Zheng et al reporting the surface initiated ATRP of 4-VBA in order to create P(4-VBA) chain grafted poly(glycidylmethacrylate- co -ethylenedimethacrylate) beads. It was shown that these materials were suitable for the enrichment of glycoproteins in complex biological samples including human serum samples to allow straightforward glycoproteome analysis [32,33]. Similar results were obtained using BA-functionalized nanodiamonds allowing the recovery of up to 75% of glycopeptides in biological samples [34].…”