Hydroxyapatite formation on/in biodegradable chitosan hydrogels by an alternate soaking process

Assessment was made of the feasibility of forming hydroxyapatite on/in naturally occurring swollen biodegradable chitosan hydrogels through an alternate soaking process. This study focused on the effects of crosslinking and swelling on hydroxyapatite formation. Two chitosan solutions (1.75 wt% and 1.5 wt%) were prepared at various glutaraldehyde (GA) feed to obtain appropriate network structures. The amount of hydroxyapatite formed increased with swelling and decrease in crosslinking density. The hydrogel prepared from the 1.75 wt% chitosan solution showed more hydroxyapatite formed on/in the swollen chitosan hydrogel matrix than the 1.5 wt% chitosan solution hydrogel at the same GA feed and/or swelling. The swelling of the chitosan-hydroxyapatite composites was smaller than that of the chitosan hydrogel. The three-dimensional structure of the hydroxyapatite composite could be controlled by manipulating certain parameters of the starting chitosan hydrogel.