Orchestrating molecular threads into functional networks: Supramolecular hydrogels as dynamic scaffolds for enzyme immobilization and catalysis.

Enzymes are excellent biological catalysts that facilitate certain biochemical reactions; nevertheless, their structural fragility, inadequate operational stability, and restricted reusability hinder their extensive commercial adoption. Enzyme immobilization has become a viable approach to overcome these limitations, with supramolecular hydrogels (SMHs) receiving considerable focus for their biomimetic microenvironments, superior biocompatibility, stimuli-responsiveness, and adjustable three-dimensional networks created via dynamic non-covalent interactions. Although there is growing interest in SMHs and enzyme immobilization independently, its amalgamation as a coherent scientific research topic is yet largely unexplored. This review addresses the gap by systematically analyzing the molecular interactions that dictate SMH formation, including hydrogen bonding, π-π stacking, electrostatic forces, and hydrophobic interactions, followed by a critical assessment of the principal SMH classes utilized in enzyme catalysis, such as peptide-based, polymer-based, polysaccharide-based, and hybrid systems. Strategies for enzyme incorporation, involving as physical entrapment, adsorption, covalent and supramolecular coupling, in situ co-assembly, enzyme-triggered gelation, and multienzyme cascade systems, are also examined. Moreover, recent applications of SMH-enzyme hybrids in biotransformation, biosensing, biomedicine, and environmental remediation are emphasized. The review offers a thorough foundation for comprehending and constructing SMH-based enzyme systems and is anticipated to shed light on future advancements in this growing interdisciplinary domain.