Adhesive Photoinitiator Constructs Polymer Jackets on Enzymes: Direct, Release‐Free Cytosolic Delivery

ABSTRACT Enzyme therapeutics require both catalytic activity and efficient cytosolic delivery—yet protective encapsulation typically compromises enzymatic function, while achieving cellular uptake without lysosomal degradation remains challenging. We address this with a rationally designed supramolecular adhesive photoinitiator ( Gu CD⊃BP‐SH) that unifies surface adhesion, radical initiation, and membrane translocation within a single host‐guest architecture. Guanidinium (Gu + ) motifs on a cyclodextrin scaffold ( Gu CD) enable non‐covalent adhesion to protein surfaces at carboxylate‐rich regions; the cyclodextrin cavity hosts a thiol‐benzophenone guest (BP‐SH) whose photoactivation (365 nm, 60 mW cm −2 for 30 min) initiates localized grafting‐from polymerization, constructing a semi‐permeable polymer jacket. Applied to β ‐galactosidase, this yields sub‐100 nm multi‐enzyme nanoassemblies (containing ∼10 enzymes per particle) retaining ∼30% catalytic activity with exceptional proteolytic resistance: 86% activity retained versus 25% for unprotected enzyme after Proteinase K challenge. The incorporated Gu + motifs enable efficient, energy‐independent cytosolic delivery via membrane translocation, with 91% of cells showing catalytic activity compared to 5% with non‐jacketed enzyme. This modular strategy confers protection and cell‐penetrating capability onto native biomacromolecules while maintaining catalytic function, eliminating the need for enzyme release—a persistent bottleneck in therapeutic delivery.