Kinetic-Controlled Synthesis of Walnut-like Core–Shell Magnetic Mesoporous Silica Microspheres for Enhanced Enzyme Loading and Biocatalytic Performance

Magnetic mesoporous materials, integrating magnetic nanoparticles and mesoporous structures, have great potential in biomedicine, catalysis, and the environment. This study develops a novel core–shell nanocarrier (CS-WMM: magnetic core-flower-like MnO₂ mesoporous layer-silica shell) for efficient lipase immobilization and enhanced phytosterol esters synthesis. Via a surfactant-free kinetic-controlled interfacial assembly, walnut-like dual-mesoporous microspheres (inner flower-like MnO₂, outer mesoporous SiO₂: 4.8 nm pore, 158.61 m²/g surface) are constructed, enabling a high enzyme loading (210 mg g^–1) and improved substrate diffusion. Compared with Fe₃O₄@MnO₂, CS-WMM achieves 78.33% esterification conversion and retains 55.03% activity after 7 cycles via dual-mesoporous synergy. This work provides a novel material design strategy with high loading capacity and structural stability for hydrophobic substrate-driven biocatalytic systems, which holds potential applications in food lipid processing, biopharmaceuticals, and other fields.