NIR‐Triggered Janus Nanofiber Dressing with Synergistic Photodynamic Antibacterial Action and Sustained Oxygen Release for Accelerated Healing of Infected Wounds

Abstract Impaired wound healing poses life‐threatening risks due to uncontrolled multidrug‐resistant bacterial infections. Although photodynamic therapy (PDT) represents a promising non‐antibiotic strategy to combat antibiotic‐resistant pathogens, its efficacy in wound dressings faces two fundamental limitations: inadequate light penetration depth hindering photosensitizer activation and hypoxia suppressing reactive oxygen species generation. To address these limitations, a near‐infrared (NIR)‐activated multifunctional bilayer Janus nanofibrous dressing featuring asymmetric hydrophobicity/hydrophilicity is engineered. This bilayer architecture integrates three synergistic functions: i) A hydrophilic CaO 2 ‐doped inner layer enabling quick blood absorption and oxygen release, promoting cell proliferation and tissue regeneration. ii) A hydrophobic outer layer with embedded NaYF 4 :Yb,Er@mSiO 2 @Ce6 achieving NIR‐triggered singlet oxygen ( 1 O 2 ) to eradicate bacteria. iii) Continuous oxygen supply from the hydrophilic layer, sustaining the photosensitization for the PDT process and thus overcoming the hypoxic‐induced limitations. In vitro and in vivo studies demonstrate the designed Janus nanofibrous dressing's excellent biocompatibility, rapid hemostasis, and near‐complete bacterial eradication (>99.99%). By synchronizing hemostasis, oxygenation, and hypoxia‐alleviated PDT, this platform significantly accelerates the healing of infected wounds through sequential hemostasis‐proliferation‐remodeling phases within 12 days, achieving near‐complete recovery compared to only 47.6% in the control group. This work provides a promising strategy for designing new dressings for infected wounds.