Multifunctional and Recyclable Photothermally Responsive Cryogels as Efficient Platforms for Wound Healing

A growth in the use of antibiotics and the related evolution of patients' drug resistance calls for an urgent response for the development of novel curing approaches without using synthetic antibiotics. Here, the fabrication of a low-cost cryogel for wound dressing applications is demonstrated. The cryogel is composed of only naturally derived components, including chitosan/silk fibroin as the scaffold and tannic acid/ferric ion (TA/Fe³⁺) as the stimuli-responsive agent for photothermal therapy. Based on the multiple weak hydrogen bonds and metal ligand coordination, the cryogel exhibits good flexibility and recoverability. Its highly porous structure renders the cryogel to be strongly hygroscopic to absorb blood for hemostasis. The cryogel exhibits excellent antibacterial activity to both Gram-negative and positive bacteria, benefiting from the high photothermal transition activity of the TA/Fe³⁺ complex. Furthermore, the cryogel can efficiently promote cell proliferation in vitro. Significantly, animal experiments also reveal that the cryogel effectively eradicate microbes at the wound and accelerate the wound healing process. In summary, this novel biorenewable cryogel demonstrates excellent hygroscopic and hemostatic performance, photothermal antimicrobial activity, and accelerates skin regeneration, which has great application potential as a promising wound dressing material in the clinical use.