Mineralized layered films of xanthan and chitosan stabilized by polysaccharide interactions: A promising material for bone tissue repair.

Mineralized films are interesting biomaterials to repair bone defects. They can be easily shaped into bone defect and be permeated by body fluids as well as allow cell proliferation. Xanthan and chitosan films mineralized with hydroxyapatite prepared and characterized in this work showed an improved film stability and controlled swelling degree when dipped in different pH buffers. The layer-by-layer technique used in the film's preparation associated with the behaviour at different pH allowed to explore separately each interaction - polysaccharide-polysaccharide and polysaccharide-ions. The entanglement between polysaccharides, the interaction of the oppositely charged polysaccharides ionic groups (amine for chitosan and carboxylate for xanthan) and the interaction with Ca ions confers a pH-responsive behaviour to the films. The mineralization with in situ hydroxyapatite formation resulted in an additional stability in the mineral phase. It has lower crystallinity similar to bone mineral as confirmed by X-Ray diffractogram. The films that were dipped in calcium phosphate solution during their production had positive results with in vitro cell adhesion test using MG63 cells culture.