Hierarchical magnetic core–shell nanoarchitectures: non-linker reagent synthetic route and applications in a biomolecule separation system

Abstract

The creation and expansion of addressable magnetic core–shell heteronanoarchitectures in a facile and economic way still remain a synthetic challenge. Herein, a novel in situ solvothermal-coating/decomposition approach has been designed and developed to manufacture a series of multifunctional magnetic core–shell heteronanoarchitectures (designated as Fe₃O₄@NiO and Fe₃O₄@Co₃O₄). Through a facile in situ coating and calcining technique without any linker shell and complex synthesis route, the resulting core–shell heteronanostructures which are composed of a magnetite core and an immobilized metal oxide surface present a number of important features, such as controllable shell thickness, excellent magnetism, stable recyclability as well as large surface-exposure area. By taking advantage of the high affinity of metal ion on the shell surface toward biomolecules and rapid response toward an assistant magnet, the heteronanoparticles (Fe₃O₄@NiO) can be applied to magnetically separate His-tagged proteins from a cell lysate and efficiently enrich peptides with different molecular weights from complex sample systems for mass spectrometry analysis. By constructing these two types of magnetic core–shell heteronanoarchitectures as examples, we have demonstrated a new possible route to generate versatile multifunctional nanostructures with distinct architectures and chemical compositions. Significantly, we expected that our approach can be extended to other potential systems such as energy conversion, information storage, water treatment as well as industry catalysis by altering the immobilized metal oxide surface and the controllable shell thickness.