Synthesis Of Covalent Organic Frameworks (COFs) And Its Application In Glycopeptide Enrichment

Covalent organic frameworks?COFs?are a new emerging class of crystalline porous materials,which are constructed with organic blocks via covalent bonds.The fabrication of COFs is driven by reversible and thermodynamically controlled reaction,which innovates their diversities in construction of building blocks,geometrical structure,and functionalization.The features,periodic skeletons,tunable and ordered nanochannels,good chemical and thermal stability,easy modification with functional groups,have arouse a desire in material scientists to extend its applications in gas storage,catalysis,and optoelectronic fields.Different from these conventional applications of COFs,herein,a new mesoporous material has been synthetized for improving the efficiency in glycopeptides/glycoproteins enrichments and separations.As an important modulators and regulars in biological processes?e.g.immune response,cell-cell communication and adhesion,fertilization,etc.?,it is not surprising that glycans occupy an important and unique place in research on glycochemistry and glycotechnology.However,the pathological glycans found on the exterior surface of cytomembrane are extremely low abundant,thus making it a challenge to recognize the targeted glycans/glycopeptides/glycoproteins from the complex biosamples.The inherent surrounding biomolecules with high-abundance would lower the accuracy and specificity in capturing the targets.In respect of that,high specific surface area,unique frame structure and satisfied functional groups of COFs could provide sufficient contact areas and adequate binding sites for the enrichment of glycopeptides/glycoproteins in a wider range of experiment conditions,benefiting the development of bio-devices or biomaterials in glycoproteomic,disease diagnose and new drug development.Herein,a new chromatographic material?phyenylboronic-acid functionalized COFs,PBS-TPB-DMTP-COF?was prepared for selective enrichment of glycopeptides by taking advantage of reversible boronic acid-diols and its stability to acid-base.In our study,via solvothermal method,the methoxy groups from2,5-dimethoxy benzene-1,4-2 formaldehyde?DMTA?was introduced to each phenyl group?from 1,3,5-Tris?4-aminopheny?benzene?TAPB??edge for the reinforcement of the interlayer interactions and stabilization of its crystallization.After that,the-N=C-groups of TPB-DMTP-COF was reduced to–NH-CH-groups for chemical modification with phyenylboronic acid.The prepared PBS-TPB-DMTP-COF SPE column was used for investigating the separation capacity in digested Fetuin glycopeptides enrichment.Ordered nanochannels,high specific surface areas,satisfied crystallinity,well stability and adequate functional groups contributes to the successful capture of glycopeptides by phyenylboronic-acid functionalized materials.The characteristic peaks(C=N:1600 cm^-1)in inferred spectroscopy?IR,Figure2-3?,the appearance of nitrogen?B?element signal content in X-ray photoelectron spectroscopy?XPS,Figure 3-6?demonstrated phyenylboronic acid had been successfully immobilized onto the TPB-DMTA-COF surface,the high specific surface area as much as 824 m²g^-1?BET,Figure 2-5?,highly crystalline?XRD,Figure2-6?,clear lattice fringes?TEM,Figure 2-6?,36 glycopeptides signals were detected with bare?MS,Figure 3-13?.The results demonstrated that PBS-TPB-DMTA-COF has a strong anti-interference ability toward non-glycopeptide signals in the capture of glycopeptides,and provided a new promising route the fabrication of chromatographic materials.