Construction of a dual-compartment hydrogel by protein-based triblock copolymer for the in situ delivery of volatile bioactives in inflamed environments

Abstract

Naturally occurring volatile bioactives, such as allyl isothiocyanate (AITC), represents a class of potent antimicrobial candidates, yet their clinical translation is severely hindered by inherent volatility and mucosal irritation. On the other hand, the prevalent extracellular acidification characteristic of inflammatory environments provides a unique pathological trigger for designing non-antibiotic therapies. Bioinspired by botanical defense systems, we constructed a mildly-acidic-responsive dual-compartment hydrogel system using a genetically programmed ABC-type protein triblock copolymer. This platform integrates a pH-responsive ferritin subunit (A block) for substrate (allyl glucosinolate, GS) encapsulation, a fibrous tropomyosin subunit (B block) for enzyme (myrosinase) hosting, and a His-tag (C block) for metal-ion coordinated cross-linking. Our designed dry powder microgels, delivered via tracheal infiltration, can be strategically deposited throughout the respiratory tract. Upon rehydration in the acidic microenvironment of inflamed lungs, the hydrogel triggers the in situ generation of highly volatile AITC, ensuring comprehensive bioactivity coverage from the conduction airway to the distal alveoli. In a murine pneumonia model, this system significantly attenuated pulmonary inflammation and tissue damage. This study establishes a custom-tailored, dual-compartment proteinaceous platforms for the delivery of volatile bioactives across diverse inflammatory pathologies.