Chitosan gel formation via the chitosan–epichlorohydrin adduct and its subsequent mineralization with hydroxyapatite

A novel hybrid material of chitosan–hydroxyapatite (HAp) composite gel is proposed. The introduction of epoxy ring onto chitosan via phthaloylchitosan to obtain a precursor from homogeneous DMF solution is demonstrated. The reaction of the precursor with hydrazine in water gives the recovery of amino groups as well as the ring opening reaction of oxirane for gelation. An alternate soaking with calcium and phosphate solution develops HAp mineralization and initiates the gel strength. Cell culture studies reveal 50% cell adhesion, whereas the mineralization with HAp reduces the cell adhesion.