Photo-triggered multifunctional gold-based hybrid nanoflowers promote infectious skin regeneration

The skin wound-healing under infectious conditions remains challenging owing to the lack of efficient strategies to inhibit drug-resistant bacteria growth and control inflammation. Photothermal therapy shows efficient antimicrobial effects, whereas it generates excessive heat to damage tissue and inflammation to impair tissue regeneration. Herein, we develop the multifunctional gold-based nanoflowers incorporated with photosensitizer (Ce6, for PDT) and anti-inflammatory drug (bromfenac sodium/BS). This allows for a nanosystem to combine the mild-photothermal therapy (mPTT), photodynamic therapy (PDT), and drug-controlled release anti-inflammation therapy for infectious skin regeneration. Upon laser irradiation, the local temperature increased (to a mild temperature of ∼ 45 ℃, mPTT) along with the singly linear oxygen (from PDT) for anti-infection; the release of BS was triggered for anti-inflammation. The multifunctional nanoflowers achieved 99 % antibacterial efficiencies and biofilm inhibition in vitro. They showed good biocompatibility and improved wound-healing in the animal models of subcutaneous abscess and skin wound infected with drug-resistant bacteria. In addition to the antibacterial effect from mPTT and PDT, the nanoflowers regulated the immune microenvironment by controlled releasing BS, inhibiting inflammation and promoting growth factor production, collagen deposition, and angiogenesis to improve skin wound-healing. Therefore, this study provides an advanced nano-system with photo-triggered antimicrobial and anti-inflammation activities, which improves infectious skin tissue regeneration.