Preparation of Fe3O4@PMAA@Ni Microspheres towards the Efficient and Selective Enrichment of Histidine-Rich Proteins

Magnetic material is considered to as a major concern material for the enrichment of histidine-rich proteins (His-proteins) via metal-ion affinity. In this work, magnetic polymer microspheres with core–shell structure (Fe3O4@PMAA@Ni) were successfully prepared via reflux-precipitation polymerization followed by in situ reduction and growth of Ni2+. The obtained Ni nanofoams with flower-like structure and uniform pore size (3.34 nm) provided numerous binding sites for His-proteins. The adsorption performance of Fe3O4@PMAA@Ni microspheres for His-proteins was estimated via selectively separating bovine hemoglobin (BHb) and bovine serum albumin (BSA) from a matrix composed of BHb, BSA, and lysozyme (LYZ). The results indicated that Fe3O4@PMAA@Ni microspheres could efficiently and selectively separate His-proteins from the matrix, with a maximum adsorption capacity of ∼2660 mg/g for BHb. Moreover, Fe3O4@PMAA@Ni microspheres exhibited good stability and recyclability for BHb separation over seven cycles. Therefore, this work reported a novel and facile strategy to prepare core–shell Fe3O4@PMAA@Ni microspheres, which was promising for practical applications of His-protein separation and purification in proteomics.