Bioadhesive and drug-loaded cellulose nanofiber/alginate film for healing oral mucosal wounds.

Recurrent oral ulcers are common oral mucosal lesions that severely reduce patients' quality of life. Commercial mucoadhesive films are easily disrupted due to oral movement and complex wet environments, thus reducing drug utilization and even causing toxic side effects. Herein, we report a mucoadhesive film composed of Ca-crosslinked carboxymethylated cellulose nanofibers and alginate, in which two drugs of dexamethasone (DXM) and dyclonine hydrochloride (DYC) are loaded for the treatment of oral ulcers. The wet films have a high Young's modulus of 7.1 ± 2.6 MPa and a large strain of 53.6 ± 9.8 % and adhere to tissue strongly, which allows them to resist the deformation caused by frequent oral movement. The films also have nice durability against water and excellent biocompatibility. Moreover, the drug release was controlled at different rates. The fast release of DYC facilitates the quick relief of pain, while the slow release of DXM benefits the long-term treatment of wounds. Finally, the animal experiment demonstrates the films displayed excellent therapeutic efficacy in healing oral ulcers.