Biocompatible chitosan based hydrogels for potential application in local tumour therapy.

A series of hydrogels based on chitosan polyamine and nitrosalicylaldehyde were prepared via dynamic covalent chemistry (DCC), by imination and transimination reactions towards ordered clusters which play the role of crosslinking nodes of the chitosan network. The hydrogelation mechanism has been proved through NMR and FTIR spectroscopy, X-ray diffraction and polarized light microscopy. The successful preparation of the hydrogels and their mechanical properties were further investigated using rheological measurements. By electron scanning microscopy, the hydrogels exhibited a channels microstructure morphology which critically influenced their fast swelling by capillarity. The hydrogels cytotoxicity was explored in vitro on HeLa cancer cells and their biocompatibility was monitored in vivo by subcutaneous implantation on rats. The novel hydrogels proved good in vitro cytotoxicity on the HeLa cells and also in vivo biocompatibility in rats. Thus, these novel biomaterials promise to be suitable for local cancer therapy.