Microneedle delivery platform integrated with Staphylococcus epidermidis-derived extracellular vesicles-based...

Due to the difficulty of overcoming the abnormal epidermal barriers and addressing S. aureus infections without disrupting indigenous skin microbiota, effective treatment of bacterial infection atopic dermatitis (AD) remains a significant clinical challenge. Skin microbiota-derived extracellular vesicles (EVs) shows protentional for skin disease treatment, but the lack of antimicrobial activity and limited skin penetration hamper their application in bacterial infection AD treatment. Here, we developed novel nanoantibiotics by loading Lev into S. epidermidis-derived EVs (Lev@SE-EVs), with supreme antimicrobial activity, regulating epidermal immune responses and enhanced epidermal barrier functionality. The nanoantibiotics were further integrated into hyaluronic acid-based microneedle (MN) for efficient transdermal delivery of therapeutic agents and effectively treating bacterial infection in AD. Upon insertion into the skin, the rapidly released Lev@SE-EVs from MN are uptake by S. aureus in a selective manner, fibroblasts, and surrounding immune cells to exert therapeutic effects in the infected dermal layer, resulting in mitigated skin inflammation, reduced S. aureus burden and increased dermis repair. Notably, Lev@SE-EVs induce IL-17A⁺ CD8⁺ T-cell accumulation in the skin in an unrelated inflammation manner, which may represent heterologous protection. This EVs-integrated MN assisted Lev@SE-EVs to alleviate skin inflammation, repair skin, and provide an effective and safe therapeutic approach for bacterial infection AD treatment.