A novel rGR-TiO₂-ZrO₂ composite nanosheet for capturing phosphopeptides from biosamples

Area of Science:

• Materials Science
• Biochemistry
• Analytical Chemistry

Background:

• Phosphopeptide enrichment is crucial for understanding cellular signaling pathways.
• Existing methods often face limitations in specificity and capacity when dealing with complex biological matrices.
• Developing advanced materials with high affinity for phosphopeptides is essential for proteomic studies.

Purpose of the Study:

• To synthesize and characterize a novel graphene oxide-titanium dioxide-zirconium dioxide (rGTZ) composite nanosheet.
• To evaluate the rGTZ composite's efficiency in capturing phosphopeptides from various complex biological samples.
• To demonstrate the superiority of the rGTZ composite over existing materials for phosphopeptide enrichment.

Main Methods:

• Sol-gel method and hydrothermal treatment for synthesizing the rGTZ composite nanosheet.
• Transmission Electron Microscopy (TEM) for nanoparticle size analysis.
• Langmuir model for evaluating adsorption behavior and calculating maximum adsorption capacity (Qmax).
• Optimization of phosphopeptide enrichment conditions using beta-casein as a standard.
• Application of the rGTZ composite to enrich phosphopeptides from diverse complex samples including milk and animal organs.

Main Results:

• The rGTZ composite nanosheet exhibited a high maximum adsorption capacity (Qmax) of 490.2 mg g⁻¹, surpassing commercial TiO2 (373.1 mg g⁻¹) and the GTZ composite (250.0 mg g⁻¹).
• TEM analysis confirmed nanoparticles with an average diameter of 100 nm loaded onto the graphene surface.
• Successful enrichment and identification of a significant number of phosphopeptides from complex samples, including 1980 phosphopeptides from mouse brain and 577 from mouse liver.

Conclusions:

• The synthesized rGTZ composite nanosheet offers an effective and highly efficient platform for phosphopeptide enrichment.
• Its integrated properties of high surface area and specific affinity enable superior capture of phosphopeptides from complex biosamples.
• The rGTZ composite demonstrates significant potential for advancing phosphoproteomics research by enabling deeper insights into biological systems.