Development and optimization of the production procedure of biphasic scaffolds for osteochondral tissue engineering

Abstract

Scaffolds used for osteochondral tissue engineering should comprise two distinct regions: a bottom region with characteristics corresponding to bone tissue, such as a porous structure with mineral components (predominantly hydroxyapatite), and a top region with characteristics of articular cartilage, which is gelatinous with high water content. In this work, we have investigated possibilities to formulate and optimize a procedure for obtaining such biphasic scaffolds based on gellan gum (GG). A porous base layer of the scaffold was obtained by lyophilization of the 2 % GG hydrogel with dispersed bioactive glass nanoparticles, as hydroxyapatite precursors. Next, different procedures were investigated to produce the upper GG hydrogel such as partial immersion of the porous layer in the GG solution and pouring the GG solution over the porous layer at different moisture conditions and temperatures. A simple mathematical model was derived and subsequently experimentally validated to find optimal temperatures of the porous layer, GG solution and the surrounding environment to provide adequate gelation rate to form the GG hydrogel on top of the porous layer with a thin interfacial zone.