In Situ Cascade Derivation toward a Hierarchical Layered Double Hydroxide Magnetic Absorbent for High-Performance Protein Separation

Selective enrichment and purification of histidine (His)-rich protein from complex mixtures is vital to satisfy the requirements of proteomic and diagnostic applications, but it still remain a challenge. Herein, a high-performance layered double hydroxide (LDH)-based adsorbent is designed and prepared, via a metal–organic framework (MOF)-mediated in situ cascade derivation strategy, for enhanced His-rich protein separation. Importantly, the pseudomorphic conversion of Fe3O4 nanoparticle-derived magnetic MIL-100(Fe) MOF, with unique structural features, enables the finally derived LDH with plenty of Ni2+ ions exposed for His-rich protein binding. As such, the as-prepared Fe3O4@NiFe LDH exhibits favorable selectivity for His-rich protein adsorption with bovine hemoglobin (BHb) as a model and with a relatively high binding capacity of 3287.67 mg g–1 in a rapid equilibrium time of 20 min, which is superior to those reported magnetic adsorbents. Also, the high performance of Fe3O4@NiFe LDH can be facilely regenerated and applied to separate BHb from a bovine blood sample, highlighting its good practicality. Therefore, this MOF-mediated cascade derivation strategy is a promising way to design advanced layered double hydroxide magnetic adsorbents for high-performance bioseparation.