Click-hydrogel delivered aggregation-induced emissive nanovesicles for simultaneous remodeling and antibiosis of deep burn wounds

As a high-risk trauma, deep burns are always hindered in their repair process by decreased tissue regeneration capacity and persistent infections. In this study, we developed a simultaneous strategy for deep burn wounds treatment using functional nanovesicles with antibacterial and tissue remodeling properties, delivered via a click-chemistry hydrogel. An aggregation-induced emission photosensitizer of 4-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)vinyl)-1-(2-hydroxyethyl) pyridin-1-ium bromide (THB) with excellent photodynamic properties was first prepared, and then combined with readily accessible adipose stem cells-derived nanovesicles to generate the THB functionalized nanovesicles (THB@ANVs). The THB@ANVs showed strong antibacterial activity against Gram-positive bacteria (up to 100% killing rate), and also beneficial effects on tissue remodeling, including promoting cell migration, cell proliferation, and regulating immunity. In addition, we prepared a click-hydrogel of carboxymethyl chitosan for effective delivery of THB@ANVs on wounds. This hydrogel could be injected to conform to the wound morphology while responding to the acidic microenvironment. In vivo evaluations of wound healing revealed that the THB@ANVs hydrogel dressing efficiently accelerated the healing of second-degree burn wounds by reducing bacterial growth, regulating inflammation, promoting early angiogenesis, and collagen deposition. This study provides a promising candidate of wound dressing with diverse functions for deep burn wound repair.