Bacterial cellulose-based flexible phase change gel for potential release-controllable wound dressings

Long-term protection of skin-defect wounds is challenging for the common wound dressings cotton gauze due to its weak skin adhesion, limited drug-loading capacity and frequent replacement. Hydrogels are considered as the promising wound dressings benefiting by their good mechanical compatibility and biocompatibility. Nevertheless, the hydrogels always suffer from the drawbacks of fast water evaporation, lack of antibacterial ability and uncontrollable drug release, which greatly shorten their long-term wound protection duration. Herein, a novel and multifunctional phase change gel (PCG) combining flexibility of hydrogel and release-controllable ability of phase change materials (PCMs) was fabricated through a facile solvent-exchange strategy. Specifically, the bacterial cellulose (BC)/polyethylene glycol based phase change gels (BC/PEG PCGs) were prepared by direct impregnation of BC hydrogel into massive PEG melts. The solvent-exchange mechanism between BC hydrogel and PCM melts was firstly studied based on the impregnation experiments of BC gels into various PCMs. The as-prepared BC/PEG PCGs were then characterized in terms of structure, mechanical, phase change and wound dressing properties, subsequently. This work provides a comprehensive understanding of the structure relationship on their excellent flexibility, good adhesive, skin-cooling, antibacterial and controllable drug-release functions of BC/PEG PCGs, extending their potential in the long-term protection of skin-defect wounds.