Unlockable Nanocaged Photodynamic Nanofiber Membranes for pH-Responsive Antibacterial Therapy via Rose Bengal Encapsulation in ZIF-8

A pH-responsive bacterial cellulose (BC)-based composite nanofiber membrane functionalized with rose bengal (RB)-encapsulated ZIF-8 (BC/RB@ZIF-8) was developed via in situ growth for the targeted therapy of bacterial stomatitis. The BC film enhanced the photodynamic effect, addressing the challenges of photosensitizer aggregation-induced quenching and its reuse. The BC/RB@ZIF-8 nanofiber membrane demonstrated sustained photodynamic activity, maintaining a stable singlet oxygen (¹O₂) quantum yield under continuous 130 min irradiation. The nanofiber membrane exhibited robust mechanical properties, including a tensile strength greater than 33 MPa, high water absorption capacity (916.61 ± 4.7%), and optimal moisture vapor transmission rate (40.56 ± 1.37 g/m²·h), meeting the key requirements for oral wound dressings. In acidic infection microenvironments, ZIF-8 degradation facilitated the synchronized release of Zn²⁺ and RB, leading to dual-mode antibacterial action: (1) the continuous release of Zn²⁺ from ZIF-8 disrupts bacterial cell membranes through electrostatic interactions; and (2) ROS generation via Type I (•OH) and Type II (¹O₂) pathways, resulting in irreversible damage to bacterial cell membranes and components. This synergistic mechanism led to a 99.99% eradication of S. aureus and MRSA under acidic conditions, outperforming conventional therapies. Cytocompatibility and hemocompatibility were confirmed in accordance with ISO 10993 standards. The BC/RB@ZIF-8 nanofiber membrane represents a significant advancement in pH-responsive antibacterial materials, offering a promising alternative to antibiotic-based treatments for biofilm-infected oral wounds.