Enzymatically biomineralized chitosan scaffolds for tissue-engineering applications.

Porous biodegradable scaffolds represent promising candidates for tissue-engineering applications because of their capability to be preseeded with cells. We report an uncrosslinked chitosan scaffold designed with the aim of inducing and supporting enzyme-mediated formation of apatite minerals in the absence of osteogenic growth factors. To realize this, natural enzyme alkaline phosphatase (ALP) was incorporated into uncrosslinked chitosan scaffolds. The uncrosslinked chitosan makes available amine and alcohol functionalities to enhance the biomineralization process. The physicochemical findings revealed homogeneous mineralization, with the phase structure of the formed minerals resembling that of apatite at low mineral concentrations, and similar to dicalcium phosphate dihydrate (DCPD) with increasing ALP content. The MC3T3 cell activity clearly showed that the mineralization of the chitosan scaffolds was effective in improving cellular adhesion, proliferation and colonization.