3-Diethylaminopropyl isothiocyanate modified glycol chitosan for constructing mild-acid sensitive electrospinning antibacterial nanofiber membrane

Bacterial infections would cause pathological inflammation and even generate chronic wound. Herein, a ciprofloxacin (Cip)-loaded mild acid-responsive electrospinning nanofiber membrane (NFM) containing 3-diethylaminopropyl isothiocyanate material grafted glycol chitosan (GC-DEAP) was fabricated to prevent bacterial infection against hemostatic and inflammatory phases of wounds. The presence of Cip and GC-DEAP in the objective NFM (PCL/GC-DEAP/Cip) was confirmed through XRD and FTIR. Meanwhile, PCL/GC-DEAP/Cip NFM exhibited high mechanical profiles, suitable water absorption and water vapour transmission ratio. The nonprotonated amphiphilic GC-DEAP under pH 7.4 facilitated the formation of uniform and smooth nanofibers with polycaprolactone (PCL) and Cip. However, the GC-DEAP was demonstrated to sharply respond to the mild acid environment of the wound and effectively be protonated, and thus improved the swelling ability of NFM and triggered burst release of Cip. Due to the combination between protonated GC-DEAP and Cip, PCL/GC-DEAP/Cip NFM achieved attractive antibacterial activity in the mild-acid environment in vitro, and induced more efficient prevention of wound infection and faster wound healing compared with the commercial chitosan dressing. The designed NFM is expected to be a potential smart wound dressing against hemostatic and inflammatory phases with mild-acid specifically strengthened antibacterial features and satisfactory biocompatibility.