Preparation Of Maltose Functionalized Micro-nano Materials Based On Self-assembled Oligopeptides And Their Application In Enrichment And Separation

The surface functionalization of micro-nano materials was important in broadening their applications.Currently,most surface functional groups are usually immobilized on the micro-nano material surface based on chemical covalent functionalization,which suffers from multistep treatment,surface-dependence,and harsh conditions.In this paper,we report a facile and rapid method for surface functionalization of different micro-nano materials based on a maltose-modified oligopeptide with a sequence of Ala-Glu-Ala-Glu-Ala-Lys-Ala-Lys(AEK8-maltose)and applied these AEK8-maltose functionalized micro-nano materials in glycopeptides enrichment in complex biological samples and hydrophilic interaction liquid chromatography.This work includes the following two aspects:First,we report a surface functionalization method via one-step assembly of AEK8-maltose,and take a research about the AEK8-maltose functionalized magnetic nanocomposites in glycopeptides enrichment.Second,the silica microspheres were functionalized with the AEK8-maltose and used as hydrophilic interaction chromatographic stationary phases.The effects of different chromatographic conditions on retention time in hydrophilic chromatography mode were explored and separated different polar compounds.This paper includes the following three parts:Part 1:IntroductionThis chapter begins with a brief overview of glycopeptide enrichment and HILIC separation technology.First,we presented the significance and related analysis techniques of glycoproteomics,then introducted the general glycopeptide enrichment methods,matrix materials,and the self-assembly mechanism of oligopeptides.For the HILIC,the characteristics,development,application,and the type of stationary phase and its retention mechanism were mainly summarized.Finally,the purpose and main content of this work are briefly introduced.Part 2:Facile maltose-functionalization of magnetic nanoparticles based on self-assembled oligopeptides for efficient enrichment of glycopeptidesIn this chapter,a simple and rapid surface functionalization method was developed via one-step self-organization of AEK-maltose in a mild condition on the surface of SiO2@Fe3O4 and C@Fe3O4 magnetic nanocomposites to a complete coating layer dominated by ?-sheets and applied to glycopeptide enrichment.The enrichment performance of glycopeptides in the standard glycoprotein horseradish peroxidase(HRP)and human immunoglobulin(IgG)digests was investigated in detail.The experiment proved that the enrichment rate is fast(incubation for 5 min,wash for 2 min),high sensitivity(0.001 ng/?L),good selectivity(1:150),good stability and reproducibility,and successfully applied in human serum digests.Part 3:Preparation of the maltose functionalized silica HILIC stationary phase based on the AEK8-maltose and applied in separation of polar compoundsIn this chapter,carbonyl diimidazole(CDI)was used as a crosslinking agent,and AEK8-maltose was immobilized on the surface of silica to prepare a maltose-type HILIC stationary phase.This method is relatively simple compared to the conventional saccharide stationary phases,and avoiding time consuming processes.In HILIC mode,the maltose-type HILIC column separated some polar compounds,and investigated the effects of different mobile phase composition,salt concentration,pH,and temperature on the retention behavior of solute.Also,the retention mechanism matched with the typical HILIC column.It exhibits good separation efficiency and column stability in the separation of polar compounds such as amino acids,bases,water-soluble vitamins,and organic acids,and also achieves good selectivity in the separation of oligosaccharides.