Boronic acid-functionalized detonation nanodiamond for specific enrichment of glycopeptides in glycoproteome analysis

Here we present the novel functionalization of detonation nanodiamond (dND) with amino-phenyl boronic acid (APBA) assisted by poly-L-lysine (PL) and PEG-diglycolic acid (PEG) (dND-p-APBA). With the assistance of biocompatible poly-L-lysine and PEG, dND-p-APBA particles show good dispersibility in aqueous solution and plentiful boronic acid functional groups on the surface, which make it a novel material promising for glycoproteome. The dND-p-APBA particles demonstrate highly specific and efficient capture of glycopeptides from complex samples. In comparison with direct (or traditional) analysis, the novel method shows better specificity for glycopeptides even when non-glycopeptides are 40 times more than glycopeptides. Besides that, the detection sensitivity of glycopeptides could be increased 50 times by the novel strategy. Additionally, the recovery of glycopeptides is up to 72.2% and the glycopeptides even can be sensitively specifically enriched and detected in the presence of 1 M sodium chloride or 0.1% sodium dodecyl sulfate. Furthermore, in combination with liquid chromatography electronspray ionization mass spectrometry (LC-ESI-MS), the novel approach was successfully applied to characterize one fraction of mouse liver, in which 40 different N-glycosylation peptides within 34 unique glycoproteins have been identified. Accordingly, the usefulness of the functionalized dND might be a promising efficient and specific analytical platform in glycoproteome analysis.