Development of novel osteochondral scaffolds and related in vitro environment with the aid of chemical engineering principles

Abstract

In tissue engineering, collaboration among experts from different fields is needed to design appropriate cell scaffolds and the required 3D environment. Osteochondral tissue engineering is particularly challenging due to the necessity to provide scaffolds that imitate structural and compositional differences of two neighboring tissues, articular cartilage and bone, and the required complex biophysical environments to cultivate such scaffolds. This work focuses on two key objectives: first, to develop bilayered osteochondral scaffolds based on gellan gum and bioactive glass, and second, to create a biomimetic environment for scaffold characterization by designing and utilization of novel dual-medium cultivation bioreactor chambers. Basic chemical engineering principles were utilized to aid both aims. First, a simple heat transport model based on one-dimensional conduction was applied as a guideline for bilayered scaffold preparation, leading to the formation of the gelatinous upper part and a macroporous lower part with a thin, well-integrated interfacial zone. Second, a novel cultivation chamber was developed to be used in a dynamic compression bioreactor to provide possibilities for flow of two different media, such as chondrogenic and osteogenic. These chambers were utilized for characterization of the novel scaffolds regarding bioactivity and stability under dynamic compression and fluid perfusion during 14 days, while flow distribution under different conditions was analyzed by a tracer method and residence time distribution analysis.