Facile Fabrication of Magnetic Metal–Organic Framework Nanofibers for Specific Capture of Phosphorylated Peptides

Abstract

A kind of magnetic metal–organic framework (mag-MOF) nanofibers was presented; the inorganic hydroxyapatite nanowires functionalized with magnetic nanoparticles on the surface acted as the scaffolds and templates for directed assembly of MIL-100(Fe) nanocrystals (one typical MOF). The as-prepared mag-MOF nanofibers have a porous structure, high specific surface area (403.6 m 2 g –1 ), high pore volume (2.14 cm 3 g –1 ), good hydrophilicity (a water contact angle of 0°), and unique magnetic response property (4.83 emu g –1 ). With these favorable characters, the mag-MOF nanofibers exhibited high affinity capability in the specific capture of phosphorylated peptides. The mag-MOF nanofibers exhibited high selectivity (a molar ratio of bovine serum albumin digest and β-casein digest of 500:1), high detection sensitivity (0.5 fmol), desirable capture recovery (87.79%), high capture capacity (93.8 mg g –1 ) and good repeatability. Moreover, the practical applications of mag-MOF nanofibers in the selective separation and identification of phosphorylated peptides in complex biological specimens (nonfat milk digest, human serum, and human saliva) were realized. Additionally, a continuous filtering approach was proposed for phosphorylated peptide enrichment through the mag-MOF nanofiber-based membrane. The present research provides a versatile strategy for the construction of several kinds of functional MOF nanofibers with different immobilized metal ions for the selective capture and identification of targeted biomolecules.