Amorphous TiO₂ Nanotubes as a Platform for Highly Selective Phosphopeptide Enrichment

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Phosphopeptide enrichment is crucial for understanding cell signaling pathways.
• Existing methods using titanium dioxide microspheres have limitations in efficiency and selectivity.

Purpose of the Study:

• To develop and evaluate novel amorphous titanium dioxide nanotubes (TiO2NTs) and superparamagnetic iron oxide nanoparticle-decorated TiO2NTs (TiO2NTs@Fe3O4NPs) for highly selective phosphopeptide enrichment.
• To compare the performance of these new materials against established TiO2 microspheres.

Main Methods:

• Synthesis of amorphous TiO2 nanotubes and TiO2NTs@Fe3O4NPs.
• Application of these materials for phosphopeptide enrichment from simple and complex peptide mixtures.
• Analysis of enrichment efficiency and selectivity using mass spectrometry.

Main Results:

• TiO2NTs and TiO2NTs@Fe3O4NPs demonstrated significantly increased phosphopeptide enrichment efficiency and selectivity (28.7% and 25.3% higher, respectively) compared to TiO2 microspheres.
• A second elution step further enhanced phosphopeptide identification.
• Amorphous TiO2 nanotubes exhibited unique physicochemical properties beneficial for selective enrichment, reducing non-phosphorylated peptides.

Conclusions:

• Amorphous TiO2 nanotubes and their superparamagnetic counterparts offer superior performance for phosphopeptide enrichment.
• TiO2NTs@Fe3O4NPs provide the added advantage of easy handling due to superparamagnetism.
• These materials hold promise for broader applications in biomolecule enrichment.