TiO₂-functionalized mesoporous materials for sensitive analysis of multi-phosphopeptides

Protein phosphorylation as one of the most important post-translational modifications in mammalian cells regulates numerous biological processes. Here we propose a novel strategy for the selective isolation and sensitive analysis of multi-phosphopeptides based on TiO₂-gratfed mesoporous materials, in which MCM-41 and SBA-15 were chosen as the hard templates. The commercialized IMAC and TiO₂ nanopartices were further investigated in the phosphopeptide analysis for comparison. The enrichment efficiency was evaluated and measured by MALDI-TOF mass spectrometry. The results indicated that both TiO₂-SBA-15 and TiO₂-MCM-41 exhibited the preferential affinity to multi-phosphopeptides compared with the other two widely used strategies. The mesoporous TiO₂ based protocol showed highly selective and sensitive properties, where phosphopeptides could be identified at femtomole.