A biomimetic multifunctional dressing based on stratum corneum microstructure: integrating antibacterial barrier and...

The stratum corneum, which has a "brick-and-mortar" structure, serves as an impermeable barrier against pathogens while enabling gas and moisture exchange. Conventional wound dressings strive to reconcile these needs. They, often prioritize excessively porous structures, which compromise the barrier efficacy, or occlusive designs that hinder substance exchange. This leads to complications like infection, dehydration, or exudate accumulation. A biomimetic dual-layer dressing with an advanced barrier layer and regenerative bioactive components has been developed to address these limitations. Inspired by the brick-and-mortar structure, the barrier layer (Cu@KSF) was constructed using keratin microspheres (KM) and methacrylated silk fibroin, which was reinforced by photo-crosslinking and sandwich-like β-crystallites. The coordination of Cu²⁺ with keratin carboxyl groups provided a bacterial barrier and inhibition, while maintaining optimal moisture transmission (1481.3-2246.1 g m^-2 day^-1) and oxygen permeability (258.4-401.5 mg m^-2 day^-1), outperforming the commercial Tegaderm™. Also, the bioactive layer (Mas@PKM) integrated the polydopamine-coated KM (PKM) with madecassoside-loaded liposomes, enabling pH-responsive drug release, rapid exudate absorption, and antioxidative activity. Furthermore, the Cu@KSF/Mas@PKM demonstrated biocompatibility while promoting cell migration, angiogenesis, anti-inflammatory effects, and collagen remodeling. It thereby accelerated infected and scald wound healing with reduced scarring. Combining the brick-and-mortar barrier and regenerative bioactivity, this degradable dressing resolved the trade-off between barrier functionality and substance exchange, providing a scalable solution for complex wound management.