Advanced fabrication of three-dimensional bicontinuous MXene/agarose composite monoliths for high-selective rapid separation of antibodies

Conventional polysaccharide monoliths with irregular interstitial channels are suffering from low mechanical strength, specific surface areas, permeabilities and large eddy diffusion. In this work, the 3D bicontinuous MXene/agarose composite (BMAC) monoliths were facilely fabricated for the first time by a bicontinuous medium internal phase emulsion (MIPE) templating method. Poly (1-vinylimidazole) (PVIM) brushes were further grafted onto the 3D BMAC (BMAC@PVIM) monolith for highly selective enrichment of antibodies. Molecular docking simulation revealed that the adsorption mechanism of human immunoglobulin G (hIgG) on the monolith is primarily driven by multiple hydrogen bonding and hydrophobic interactions, and the optimal number of VIM units in the PVIM brush is determined to be 9. The resulting 3D BMAC@PVIM monolith exhibited a well-ordered structure, featuring a sturdy framework with diffusive mesopores (∼9 nm) and interconnected gigapores (∼10.1 μm). This composite monolith demonstrated a significantly higher specific surface area (46.6 m 2 /g), enhanced column permeability (1.67 × 10 −12  m 2 ), and increased operating flow rate (20 mL/min) compared to its counterpart (GMAC@PVIM monolith) prepared using the conventional MIPE template. Benefiting from its uniform and ordered skeleton and pore channels, the maximum equilibrium adsorption capacity of hIgG on the monolith could achieve 217.4 mg/g, which is superior to most reported separation materials. Meanwhile, the high adsorption rate constant in the film mass transfer stage also confirmed the satisfactory mass transfer efficiency of interconnected gigapores within the monolith. The 3D BMAC@PVIM monolith can efficiently purify antibodies with a purity of 94.1 % from human serum at a flow rate of 12 mL/min, demonstrating great potential in the field of rapid antibody purification.