Chitosan-based hydrogels to treat hydrofluoric acid burns and prevent infection

There is an urgent need for treatments for hydrofluoric acid (HF) burns and their derivative problems that prevent hydrogen ion dissociation and fluoride ion binding to tissues. This study evaluated the ability of chitosan-based hydrogels combined with a buffer solution containing either boric acid or Tris and calcium gluconate (CHS-BA-CG and CHS-Tris-CG) to repair HF burn wounds and prevent wound infections. We assessed calcium release rates and biocompatability and constructed a mouse HF burn model to assess the tissue repair effects of the hydrogels. Finally, we performed disc diffusion tests from burn tissue and quantified the bacterial counts to assess the anti-infection properties of the hydrogels. Calcium was gradually released in the CHS-BA-CG and CHS-Tris-CG groups (73% and 43%, respectively, after 48 h). The cell viabilities at 48 h after HF burn in these groups were significantly higher than those in the phosphate-buffered saline (PBS) and CG-treated groups. Histopathological evaluation showed a clear boundary between the epidermal and dermal layers in both CHS-BA-CG and CHS-Tris-CG-treated groups, indicating their effectiveness in tissue repair. In the disc diffusion test, CHS-BA-CG and CHS-Tris-CG exhibited larger inhibition zones against Acinetobacter baumannii than those for PBS and CG. The bacterial counts on HF burn wounds were significantly lower in the CHS-BA-CG and CHS-Tris-CG-treated groups than those in the PBS and CG-treated groups. The in vitro studies demonstrated the biocompatibility and antimicrobial effects of the CHS-BA-CG and CHS-Tris-CG hydrogels. Both gels also demonstrated tissue repair and anti-infection effects. Thus, chitosan-based hydrogels may be candidates for HF burn therapy. Graphical abstract: [Figure not available: see fulltext.].