Biomimetic immobilization of α-glucosidase in double-shelled ZIF-90 for inhibitor screening from traditional Chinese medicines.

α-Glucosidase (α-Glu) is a key therapeutic target for type 2 diabetes mellitus (T2DM), and screening α-Glu inhibitors is crucial for antidiabetic drug discovery. In this work, a rapid and efficient screening strategy was developed based on an immobilized α-Glu assay. Through a synergistic combination of biomimetic mineralization and sequential layer-by-layer growth, α-Glu was successfully encapsulated in situ within the hydrophilic zeolitic imidazolate framework-90 (ZIF-90), yielding a novel double-shelled (ZIF-90@α-Glu)2 composite. Systematic characterizations including TEM, BET, FT-IR, XRD, and XPS verified the uniform core-shell nanostructure, hierarchical porosity, high enzyme loading (51.12 μg·mg⁻¹) and immobilization efficiency of 84.5%. The immobilized α-Glu exhibited enhanced pH and temperature tolerance, excellent storage stability (retaining 71.86% of its initial activity after 35 days at 4 °C) and reusability (retaining 77.02% of its activity after 10 reuse cycles). Kinetic analysis revealed that (ZIF-90@α-Glu)2 maintained intrinsic substrate affinity (Kₘ = 1.40 mM) while exhibiting a 2.5-fold higher Vₘₐₓ value (1.995 Abs·min⁻¹) compared to free α-Glu, indicating improved catalytic efficiency. This enhancement could be attributed to the unique double-shelled ZIF-90 scaffold, which provided a protective barrier and efficient mass transfer pathways for substrates. Furthermore, the (ZIF-90@α-Glu)2 was successfully applied to screen α-Glu inhibitors from 10 traditional Chinese medicines (TCMs), among which Lycium barbarum L. leaves exhibited the strongest inhibitory activity. This study provides a promising strategy for enzyme immobilization and efficient screening of antidiabetic active components from complex natural products, especially TCMs.