Anionic clay-based nanozymes: Interfacial regulation, structural design and functional applications.

Anionic clays, also known as layered double hydroxides (LDHs) or hydrotalcites, have recently emerged as a versatile class of ion-intercalated two-dimensional colloidal anionic clay materials capable of mimicking enzymatic functions. Their tunable composition, high surface charge density and advantageous interfacial features enable properly controlled redox and biocatalytic activities, positioning them as promising candidates for the design of enzyme mimicking materials, so-called nanozymes. This review integrates the structural chemistry of LDHs with their biocatalytic performance. Two main categories are distinguished, namely, Type 1 LDH nanozymes, where enzymes or biomolecules are immobilized on or within the lamellar host, as well as Type 2 LDH nanozymes, which rely on the intrinsic redox activity of the layered structure itself. The interplay between interface regulation, ion exchange and nanoscale confinement dictates substrate accessibility and biocatalytic turnover in both systems. Representative examples demonstrate applications in antioxidant agents, antibacterial or anticancer therapies and environmental sensing. The contribution concludes by outlining conceptual and methodological frontiers that merge colloid science with emerging design paradigms, such as AI-guided materials discovery, multi-nanozyme cocktail assemblies, advanced microfluidic synthesis and environmental interfaces for detecting or degrading emerging contaminants. By uniting surface chemistry with bioinspired catalysis, LDH-based nanozymes exemplify the transformation of traditional clays into adaptive, multifunctional materials at the forefront of colloid science.