Preparation Of Biomimetic Honeycomb Membrane Material And Its Application In Glycoproteomics

In the study of glycoproteomics with mass spectrometry,certain pretreatments of samples are required for eliminating the interference of nonglycopeptides and improving the efficiency of glycopeptides detection.Although hydrophilic interaction chromatography(HILIC)has been developed for enrichment of glycosylated peptides,a plethora of hydrophilic materials always suffered from large steric hindrance,great cost,and difficulty with modifications of high-density hydrophilic groups.To solve these problems,in this paper,two novel HILIC macroporous materials have been developed for the high selectivity,high sensitivity and extensive enrichment of glycosylated peptides by using chitosan whitch is inexpensive and highly hydrophilic.(1)Biomimetic chitosan membrane with honeycomb-like structure: in this work,a 1 mm thick biomimetic honeycomb chitosan membrane(BHCM)with honeycomb-like accessible macropores was directly prepared by the freeze-casting method as an adsorbent for HILIC.The N-glycopeptides from trypsin digests of immunoglobulin G(IgG),mixture of IgG and bovine serum albumin(BSA),and serum proteins were enriched using this material and compared with a commercial material ZIC-HILIC.The biomimetic membrane could identify as many as 32 N-glycopeptides from the IgG digest,exhibiting high sensitivity(50 fmol),outstanding recovery(93.3%)and a wide scope for glycopeptide enrichment.A molar ratio of IgG trypsin digest to bovine serum albumin trypsin digest as low as 1/500 verified the outstanding specificity and efficiency for glycopeptide enrichment.In addition,270 unique N-glycosylation sites of 400 unique glycopeptides from 146 glycosylated proteins were identified from the triplicate analysis of 2 ?L human serum.Furthermore,48 unique O-glycosylation sites of 278 unique O-glycopeptides were identified from the triplicate analysis of 30 ?g deglycosylated fetuin digest.These results indicated that the chitosan-based membrane prepared in this work had great potential for pretreatment of samples in glycoproteomics.(2)Chitosan containing COF membrane: Covalent organic frameworks(COFs)are a new class of porous organic polymers with an ordered structure and high crystallinity,in which the organic building blocks are linked by strong covalent bonds.COFs that generally offer high surface area have attracted much attention in the field of adsorption.Up to now,there are few reports about COF hierarchically porous monoliths membranes.In this paper,a novel COF made by trimethyl phloroglucinol and Oxalyl dihydrazide was loaded into a chitosan membrane to obtain a hierarchically porous membranes which was applied in glycopeptide enrichment and adsorption of copperions.