Boronate Avidity Assisted by Dendrimer-like Polyhedral Oligomeric Silsesquioxanes for a Microfluidic Platform for Selective Enrichment of Ubiquitination and Glycosylation

Abstract

A new strategy of improving boronate avidity with good accessibility of sites was suggested by utilizing a dendrimerlike structure of boron materials based on octavinyl-polyhedral oligomeric silsesquioxanes (Ov-POSS). 3-(Acrylamido)phenylboronic acid (AAPBA) was used as a functional monomer and ethylene glycol dimethacrylate (EDMA) and Ov-POSS as cross-linkers. The resulting Ov-POSS cross-linked boron monolith exhibited 27 times stronger affinity for glycoproteins than the Ov-POSS-free monolith. Importantly, the bonding strength of the poly(AAPBA-co-Ov-POSS-co-EDMA) monolith to the glycoproteins with multiple sugars, horseradish peroxidase (HRP) was 4 orders of magnitude higher than that of the single cis-diol-containing compound. The resulting monolith was used as a part of a microfluidic platform for online processing of the protein extracts from mouse liver, which integrated five functions, including protein grading, denaturation, enzymatic hydrolysis, and enrichment of glycopeptides and ubiquitin-modified peptides. The sample processing time can be reduced by nearly half compared to the offline method. Moreover, 86.7% of glycopeptides and 75% of glycoproteins were newly identified after treatment. All of the results indicated that the synergistic strategy of Ov-POSS cross-linking can significantly improve trace glycosylation's binding capacity and enrichment performance. The microfluidic platform developed may provide a promising technical tool for automated, high-efficiency, high-throughput analysis for post-translational modification proteomics.

Electrochemical detection of glycoproteins using boronic acid-modified metal–organic frameworks as dual-functional signal reporters

“…Furthermore, the multivalent boronic acid tags on the surface of MOFs show nanomolar binding strength to glycoproteins, which is significantly higher than that of the complex between single boronic acid and glycan (in the micromolar range). 27 The level of PSA in the serum samples from healthy males is usually below 4.0 ng mL −1 . 62 However, the concentrations of PSA are always elevated in prostate patients.…”

“…22–26 Multivalent boronic acid tags on nano-surfaces exhibit higher binding affinity toward glycoproteins than single boronic acid molecules (usually at the micromolar level). 27–30 However, boronic acid-functionalized nanomaterials such as Au or Ag nanoparticles may suffer from complex modification steps and easy aggregation due to self-dehydration condensation between three boronic acid molecules into a 6-membered boroxine ring. 31 Metal–organic frameworks (MOFs), a large class of highly porous crystalline hybrid materials, are assembled using metal ions/clusters and multidentate organic ligands.…”

Biosensors with Boronic Acid-Based Materials as the Recognition Elements and Signal Labels

“…The relatively low affinity may limit the applications of boronic acid molecules in real-sample assays. However, when boronic acid derivatives were loaded on nanomaterials, their binding strength toward cis -diol-containing species was significantly enhanced ( K d = 10 −5 –10 −10 M) [ 254 ]. In addition, thanks to the reversible and selective sugar-responsive property of boronic acid, boronate-affinity materials have been used for in vivo labeling of cis -diol-containing species with physiological and pathological functions.…”