A novel hydrophilic polymer-coated magnetic nanomaterial based on the HILIC strategy for fast separation of glycopeptides and glycosylated exosomes.

Novel hydrophilic poly(N, N-methylenebisacrylamide/1,2-epoxy-5-hexene) coated magnetic nanospheres functionalized with 2-aminopurine (denoted as Fe3O4@poly(MBA/EH)@2AP) for enriching glycopeptides and glycosylated exosomes were successfully obtained using a simple and green method on the basis of the HILIC (hydrophilic interaction liquid chromatography) enrichment strategy. The high density of polar groups endows the material with amazing hydrophilicity, enabling the nanomaterial to successfully capture glycopeptides and glycosylated exosomes within 1 min. Meanwhile, the materials demonstrated great sensitivity (0.01 fmol/µL), good loading capability (125 µg/mg), high selectivity (BSA:HRP = 1000:1), and repeatability (more than 10 times). Besides, the material was applied in the analysis of bio-samples, a total of 290 glycosylated peptides and 184 glycosylation sites mapping to 185 glycoproteins were identified in the serum of uremic patients. Besides, 42 glycopeptides were enriched from the saliva of healthy people. At the same time, it was verified by TEM and western blot that the complete glycosylated exosomes were successfully captured from the serum of the uremic patients. All experiments have demonstrated that Fe3O4@poly(MBA/EH)@2AP has a promising future in practical applications.

Fabrication of multi-wall carbon nanotube film on glassy carbon electrode surface and the determination of tyrosine.

A novel chemically modified electrode has been prepared on the basis of the attachment of multi-wall carbon nanotubes (MWNT) onto the surface of a glassy carbon electrode (GCE) in the presence of a hydrophobic surfactant, dihexadecyl phosphate (DHP). This MWNT film was characterized by transmission electron microscopy images (TEM) and scanning electron microscopy (SEM). The electrochemical behavior of tyrosine at the MWNT film coated GCE was examined and it is found that this MWNT-modified GCE greatly enhances the oxidation peak current of tyrosine. Effects of some important factors, including pH, scan rate and amount of modifier, on the oxidation process of tyrosine were investigated. When the signal to noise ratio (SNR) is 3, the detection limit is 1 x 10(-7) M. The low relative standard deviations of the detection of tyrosine in human morning urine (3.3%) and white wine (5.2%) suggest a good reproducibility of the modified electrode.