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Magnetic Binary Metal–Organic Framework As a Novel Affinity Probe for Highly Selective Capture of Endogenous Phosphopeptides

Liu, Qianjing, Sun, Nianrong, Gao, Mingxia, Deng, Chun-hui
ACS sustainable chemistry & engineering 2018 v.6 no.3 pp. 4382-4389
coordination compounds, humans, iron oxides, magnetism, phosphopeptides, saliva, surface area
Highly efficient detection of endogenous phosphopeptides from complex biosamples is essential in phosphopeptidomics analysis due to the severe disturbance caused by the chaotic biological environment. In this study, for highly selective capture of endogenous phosphopeptides, a magnetic binary metal–organic framework (MOF) with Zr–O and Ti–O centers (denoted as Fe₃O₄@PDA@Zr-Ti-MOF) was designed and synthesized by a facile postsynthetic method. Briefly, Zr-based MOF was first coated on the surface of magnetic Fe₃O₄ with polydopamine (PDA) as a linker, and then, the as-prepared Fe₃O₄@PDA@Zr-MOF was exposed to DMF solution containing TiCl₄(THF)₂, resulting in the successful synthesis of Fe₃O₄@PDA@Zr-Ti-MOF. This newly prepared Fe₃O₄@PDA@Zr-Ti-MOF owned the merits of large specific surface area, unique porous structure, and superparamagnetism as well as the enhanced dual affinities of Zr–O and Ti–O centers toward both endogenous mono-phospho-peptides and multi-phospho-peptides, showing highly improved performance with better selectivity and sensitivity compared to single-metal centered MOFs (Fe₃O₄@PDA@Zr-MOF, Fe₃O₄@PDA@Ti-MOF). The Fe₃O₄@PDA@Zr-Ti-MOF was also successfully applied to extract endogenous phosphopeptides in biological sample of human saliva. As a result, 34 mono-phosphorylated peptides and 10 multi-phosphorylated peptides were detected from merely 1 μL of pristine human saliva, confirming its bright prospects in phosphopeptidomics analysis.