Facile synthesis of titanium(IV) ion-immobilized arsenate-modified poly(glycidyl methacrylate) microparticles and the application to the specific enrichment of phosphoproteins.

Selective separation and enrichment of phosphoproteins possess the distinct clinical and biological importance in the diagnosis, treatment, and management of several fatal human diseases. In this study, a facile synthesis of titanium(IV) ion–immobilized arsenate-modified poly(glycidyl methacrylate) microparticles (denoted as Ti4+-arsenate-PGMA-MPs) was developed for the efficient enrichment of intact phosphoproteins found in biologically complex protein samples. By virtue of the strong interaction between the titanium ions immobilized on the surface of Ti4+-arsenate-PGMA-MPs and phosphate groups of phosphoproteins, Ti4+-arsenate-PGMA-MPs had a high saturated adsorption capacity for phosphoproteins (901 mg/g for β-casein), which was much higher than that of non-phosphoproteins (73.5 mg/g for BSA). Ti4+-arsenate-PGMA-MPs were characterized by SEM, TEM, and FT-IR, and the average particle diameter was about 2.5 μm with good dispersibility. Besides, the application of Ti4+-arsenate-PGMA-MPs in real biological samples was investigated by SDS-PAGE analysis, and the results showed that Ti4+-arsenate-PGMA-MPs were able to enrich phosphoproteins efficiently.