Selective encapsulation of hemoproteins from mammalian cells using mesoporous metal oxide nanoparticles

•Mesoporous metal oxide nanomagnets (NMs) showed selective separation of hemoprotein.•The morphology, crystal size and magnetic properties of NMs affected protein adsorption.•The NiO NMs showed higher loading capacity and exceptional encapsulation of hemoglobin from RBCs.•The heme groups and protein-carrier binding energy play a key role in immobilization of proteins.•This separation model showed feasibility for single-protein adsorption from mixtures.

A key requirement in successful protein encapsulation is the fabrication of selective protein supercaptors that are not impeded by the physical shape and three-dimensional hydrodynamics of the protein, exhibit minimal clogging effect but with high protein retention, and with uniformly sized adsorbent pores. We report a novel nanomagnet-selective supercaptor approach in the encapsulation of hemoprotein from mammalian cells using mesoporous metal oxide nanoparticles (NPs). Different morphologies of mesoporous NiO and Fe3O4 NPs were fabricated. Among these nanoadsorbents, NiO nanoroses (NRs) had higher loading capacity of hemoprotein than NiO nanospheres (NSs) and nanoplatelets (NPLs), or even superparamagnetic Fe3O4 NPs. The key finding of this study was that mesoporous NiO nanomagnet supercaptors show exceptional encapsulation and selective separation of high-concentration Hb from human blood. In this induced-fit separation model, in addition to the heme group distributions and protein-carrier binding energy, the morphology and magnetic properties of NiO NPs had a key function in broadening the controlled immobilization affinity and selectivity of hemoproteins. In addition, thermodynamics, kinetics, and theoretical studies were carried out to investigate the optimal performance of protein adsorption.

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