Dressing materials face important limitations. No single product better integrates protection, wear comfort, and efficient antibacterial action. Now, researchers from Hong Kong Polytechnic University, together with collaborators from City University of Hong Kong, Jiangnan University and Zhejiang Polytechnic University, led by Professors Xungai Wang, Shuo Shi, Huiiqun Zhou and Yang Ming, have unveiled a breakthrough bionic wound dressing that bridges the gap between passive coverage and active healing.
Why this dressing is important
Traditional wound dressings typically force a trade-off between comfort and functionality. Gauze sticks to the wound and causes pain when changing. Foam dressings are expensive. Hydrocolloid dressings are not suitable for infected wounds. The new bionic cooling skin overcomes this limitation by combining a hierarchical Janus nanofiber structure with a visible light-responsive metal-organic framework (MOF), while simultaneously achieving passive thermal management, on-demand antimicrobial action, and skin-like mechanical compatibility.
Innovative design and mechanism
This material is fabricated by synergistic integration of solvent welding technology and single-sided Fe-modified zeolite imidazolate framework 8 (Fe-ZIF8). Solvent welding forms robust physical bonds between the electrospun PVDF nanofibers, resulting in a tensile strength of approximately 21.6 MPa and a strain at failure of approximately 54%, resulting in mechanical properties that closely resemble natural human skin. The Janus architecture features a hydrophobic outer layer (water contact angle = 137°) that reflects sunlight and transmits mid-infrared radiation for passive cooling, while a hydrophilic inner layer (water contact angle = 72°) wicks moisture and immobilizes Fe20-ZIF8 nanoparticles for antimicrobial functionality.
DFT simulations and UPS measurements reveal that Fe doping narrows the ZIF8 bandgap from 5.15 eV to 2.56 eV, enabling visible light absorption (>420 nm). Upon irradiation, the Fe-N4 coordination sites generate photocatalytic reactive oxygen species (ROS) with twice the signal intensity of the original ZIF8, triggering an O2/O2- redox cascade to eliminate bacteria. The high mid-infrared emissivity (80.7% in the 7-14 μm atmospheric window) is caused by the abundant IR-active CF, CC, and metal-O bonds, which enable radiative heat dissipation.
excellent performance
The bionic cooling skin offers a comprehensive set of features, including air permeability greater than 1.8 mL s-1, water vapor transmission rate greater than 12.5 kg m-2 d-1, and particle filtration efficiency greater than 99.8%. Under simulated sunlight (1 sun), the Janus structure reduces surface temperature by approximately 4 °C compared to non-Janus structures, while in an in vivo rat model it exhibits an average cooling of 1.7 °C under realistic outdoor conditions (solar irradiance: 115-195 W m-2).
In healing infected wounds, this dressing achieves 97.1% antibacterial efficacy against infection. Staphylococcus aureus While maintaining good biocompatibility with fibroblast NIH3T3 cells for 5 days under white light compatible antibiotic treatment positive control. Notably, wounds treated with bionic skin closed almost completely within 11 days, and the healing rate was more than double that of the untreated or pure PVDF group.
Mechanistic insights gained from genetic analysis
Comprehensive RNA-seq and qPCR analysis revealed that bionic skin actively controls wound repair at the genetic level. The dressing upregulates angiogenic markers (Vcam1, Vegfd, Vegfb, Vegfc), cell migration genes (Cemip, Cemip2), and antimicrobial peptides (cathelicidin, hepcidin), while downregulating inflammatory factors (Ilrun, Madcam1, TNF-α). GO and KEGG enrichment analysis confirmed significant activation of PI3K-Akt, HIF-1, and NF-κB signaling pathways, optimizing the wound microenvironment through antimicrobial, proangiogenic, anti-inflammatory, and antioxidant mechanisms. Histological evaluation showed the most uniform collagen deposition (34.06 ± 8.29%) and optimal epidermal thickness (89.50 ± 13.60 μm), which is almost twice that of normal skin, indicating robust tissue regeneration without excessive scarring.
Applications and future prospects
This study establishes a new paradigm for intelligent wound management by demonstrating that structural biomimetics and functional materials design can be seamlessly integrated. Bionic cooling skins hold great promise as next-generation biomedical materials that combine thermal comfort, active infection control, and promotion of tissue regeneration, as well as advancing the understanding of wound repair mechanisms through multi-omics analysis.
Look forward to more groundbreaking research from this collaborative team at Hong Kong Polytechnic University and partners in Hong Kong and mainland China.
sauce:
Shanghai Jiao Tong University
Reference magazines:
Shi, S. Others. (2026). Bionic cooling skin for infected wound healing. nano-micro characters. DOI: 10.1007/s40820-026-02240-6. https://link.springer.com/article/10.1007/s40820-026-02240-6
