Bionic Wound Dressing Combines Cooling, Antibacterial Action, and Skin-Like Mechanics
A research team led by The Hong Kong Polytechnic University—in collaboration with City University of Hong Kong, Jiangnan University, and Zhejiang Sci-Tech University—has developed a bionic wound dressing that integrates passive thermal management, on-demand antibacterial activity, and mechanical properties comparable to natural human skin.
Design: A Hierarchical Janus Structure
The dressing uses a dual-layer nanofiber architecture, with each side engineered for a distinct function.
- Hydrophobic outer layer (water contact angle 137°): Reflects sunlight and transmits mid-infrared radiation, helping to keep the wound cool.
- Hydrophilic inner layer (water contact angle 72°): Wicks moisture away from the wound and contains Fe-modified zeolitic imidazolate framework-8 (Fe-ZIF8) nanoparticles that enable light-activated antibacterial action.
Mechanical Properties: A Match for Natural Skin
The dressing exhibits a tensile strength of approximately 21.6 MPa and a failure strain of about 54%, closely matching the mechanical profile of natural human skin. This balance of strength and flexibility ensures the dressing conforms comfortably to the body without restricting movement.
Antibacterial Mechanism: Light-Activated Defense
Fe doping narrows the ZIF8 bandgap from 5.15 eV to 2.56 eV, enabling the material to absorb visible light.
Upon illumination, the Fe-N₄ coordination sites within the structure generate reactive oxygen species (ROS) that effectively eliminate bacteria. This on-demand mechanism means antibacterial activity is triggered only when needed.
Cooling Performance: Passive Temperature Regulation
Under simulated sunlight (1 sun intensity), the Janus structure reduced surface temperature by approximately 4°C compared to non-Janus counterparts. In live rat models tested under outdoor conditions (solar irradiance 115–195 W/m²), the dressing achieved an average cooling of 1.7°C.
Antibacterial Efficacy: Near-Complete Pathogen Elimination
The dressing achieved 97.1% efficacy against Staphylococcus aureus under white light, a result comparable to antibiotic-treated positive controls.
Wound Healing: Accelerated Recovery
In rat models, wounds treated with the dressing achieved near-complete closure within 11 days, with healing rates more than double those observed in untreated or pure PVDF groups.
Biocompatibility: Safe for Long-Term Use
The dressing maintained excellent compatibility with fibroblast NIH3T3 cells over a 5-day period, indicating it is non-toxic and suitable for extended wear.
Background and Significance
Conventional wound dressings often require trade-offs between comfort and functionality. This research addresses that limitation by combining multiple advanced features into a single, skin-mimicking material.
The work was led by Professors Xungai Wang, Shuo Shi, Huiqun Zhou, and Yang Ming at The Hong Kong Polytechnic University, with collaborators from multiple institutions.
The findings are supported by extensive experiments, including RNA sequencing, gene analysis, and histological assessment, which showed regulated wound repair through angiogenesis markers, cell migration genes, and antimicrobial peptides, while simultaneously downregulating inflammatory factors.