Stretchable and pH-sensitive liquid metal/mxene hydrogels for antibacterial environment creation and photothermal therapy of infected wounds

Wound infection remains a significant challenge in clinical medicine, impeding the healing process of wounds. Conventional therapeutic approaches, including antibiotics, surgical debridement, and conventional dressings, are often limited by issues such as antibiotic resistance, secondary tissue damage, and insufficient biocompatibility. Existing wound dressings exhibit poor mechanical properties and possess only single therapeutic functions, lacking the ability to effectively monitor wound healing status. To address these limitations, this study have developed a novel hydrogel dressing. This dressing utilizes microfibrillated cellulose (MFC) to stably encapsulate liquid metal (Ga) droplets, which also serve as a photothermal filler for the hydrogel. The addition of MXene stabilizes the colloidal system, and the resulting hydrogel is integrated with a pH-sensitive optical fiber to form a pH-sensitive optical fiber/ PMGa hydrogel. This composite hydrogel exhibits excellent mechanical properties (400 % elongation at break), antimicrobial activity, and pH sensitivity. Moreover, the hydrogel's tissue adhesion and stretchability enable it to conform to various skin surfaces and accommodate skin movement and stretching. The pH-sensitive optical fiber/PMGa hydrogel not only monitors the pH value of the wound through different light transmittance to judge the state of the wound environment， but also effectively inhibits bacterial growth through its photothermal effect. It provides an optimal temperature and humidity environment to promote cell proliferation and granulation tissue formation, thereby facilitating photothermal therapy. In summary, this work presents a novel hydrogel dressing that integrates monitoring and therapeutic functions. This comprehensive solution offers a new platform for the development of wound infection treatment materials.