Preparation of norfloxacin-grafted chitosan antimicrobial sponge and its application in wound repair

Trauma is one of the most common health issues in humans, and bacterial infection of the wound may result in many complications. In this paper, using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) as a coupling agent, chitosan (CS) was grafted with norfloxacin (NF), an antibacterial agent, to prepare a CS-NF sponge by freezing-induced phase separation. The CS-NF sponge was characterized by ultra violet-visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. Its porosity and water absorption ratio were determined, the antimicrobial activity was evaluated by inhibition zone assay, and its wound repair effect was investigated in a full-thickness cutaneous excisional wound animal model. The results showed that NF was successfully grafted onto CS, and the obtained CS-NF sponge had both a high porosity and water absorption ratio. The CS-NF sponge displayed significant antimicrobial activities in the inhibition zone assay. In vivo the CS-NF sponge exhibited a strong wound healing effect, with a wound healing rate close to 100% by day 15. Therefore, the CS-NF sponge is a novel promising wound-healing dressing for clinical practice.