Gellan-gum based bilayered scaffolds for application in osteochondral tissue engineering

Bilayered scaffold and cellular strategies are currently applied to solve the challenging problem of osteochondral defects. In this study, several formulations of Gellan gum were developed to fabricate different scaf- folds possessing a cartilage-like layer and a bone-like layer. The bone- like layers were obtained by low acyl Gellan gum (LAGG) at 2 wt% and different amounts of hydroxyapatite powders (HAp) (5,10,15 and 20wt%). The cartilage-like layers were obtained by preparing LAGG formulation at 2wt% and formulations of LAGG at 2wt% and high acyl Gellan gum (HAGG) at 0.75wt% at a ratio of 75:25(v%). The visco- elastic measurements were performed using a TRITEC8000B DMA to characterize the mechanical behaviour of the bilayered scaffolds. The effect of the incorporation of different amount of HAp within the bone- like layer on the mechanical properties of the scaffolds was also investi- gated. Degradation and water uptake studies were performed by soak- ing the scaffolds in a phosphate buffered saline solution (pH 7.4) up to 30 days. The bilayered scaffolds were investigated by stereo microscope to evaluate the interface between both layers. The cytotoxicity of the bilayered scaffolds was investigated in vitro using a L929 cell line. In vi- tro studies regarding adhesion, encapsulation and viability of human chondrocytes (cartilage-like layer) and human osteoblasts (bone-like layer) cultured in the bilayered scaffolds were also carried by perform- ing SEM analysis and Live/Dead assays.