A novel double-component MOAC honeycomb composite with pollen grains as a template for phosphoproteomics research

The enrichment and separation of phosphopeptides from mixed biological samples is a technologically very significance, but highly challenging work. Current designed materials are mainly based on the broad and effective adsorptive character of metal oxide affinity chromatography (MOAC). Though significant progress has been made in the enrichment of phosphopeptides with MOAC material, there are chances for further development. In this study, a novel pollen-based MOAC honeycomb material was firstly explored in which the suitable hydrophilic channels preferentially enrich much more endogenous phosphopeptides than nonphosphopeptides or proteins while doping binary metal oxides at the atomic level and the ultra-high specific surface area have further allowed it to possess more effective active sites. Based on these unique features, the pollen-based material exhibited high selectivity for β-casein (mass ratio of β-casein/BSA, 1:1500), ultra-low detection limit (0.1fmol), desirable reusability. Moreover, the bionics MOAC composites were investigated in the enrichment of phosphopeptides from nonfat milk, human serum (male and female at the same age) and mice liver, results of which indicate the great potential of the composite for the phosphoproteome analysis of complex biological samples through the cheap and environmentally friendly process.