Development of mesoporous TiO2 microspheres with high specific surface area for selective enrichment of phosphopeptides by mass spectrometric analysis

In this study, mesoporous TiO2 microspheres were synthesized by simple hydrothermal reaction, and successfully developed for phosphopeptides enrichment from both standard protein digestion and real biological sample such as rat brain tissue extract. The mesoporous TiO2 microspheres (the diameter size of about 1.0 μm) obtained by simple hydrothermal method were found to have a specific surface area of 84.98 m2/g, which is much larger than smooth TiO2 microspheres with same size. The surface area of mesoporous TiO2 microspheres is almost two times of commercial TiO2 nanoparticle (a diameter of 90 nm). Using standard proteins digestion and real biological samples, the superior selectivity and capacity of mesoporous TiO2 microspheres for the enrichment of phosphorylated peptides than that of commercial TiO2 nanoparticles and TiO2 microspheres was also observed. It has been demonstrated that mesoporous TiO2 microspheres have powerful potential for selective enrichment of phosphorylated peptides. Moreover, the preparation of the mesoporous TiO2 microspheres obtained by the hydrothermal reaction is easy, simple and low-cost. These mesoporous TiO2 microspheres with the ability of large scale synthesis can widely be applied for phosphorylated proteomic research.