Effects of agarose mould compliance and surface roughness on self-assembled meniscus-shaped constructs

The meniscus is a fibrocartilaginous tissue that is critically important to the loading patterns within the knee joint. If the meniscus structure is compromised, there is little chance of healing, due to limited vascularity in the inner portions of the tissue. Several tissue-engineering techniques to mimic the complex geometry of the meniscus have been employed. Of these, a self-assembly, scaffoldless approach employing agarose moulds avoids drawbacks associated with scaffold use, while still allowing the formation of robust tissue. In this experiment two factors were examined, agarose percentage and mould surface roughness, in an effort to consistently obtain constructs with adequate geometric properties. Co-cultures of ACs and MCs (50:50 ratio) were cultured in smooth or rough moulds composed of 1% or 2% agarose for 4 weeks. Morphological results showed that constructs formed in 1% agarose moulds, particularly smooth moulds, were able to maintain their shape over the 4 week culture period. Significant increases were observed for the collagen II:collagen I ratio, total collagen, GAG and tensile and compressive properties in smooth wells. Cell number per construct was higher in the rough wells. Overall, it was observed that the topology of an agarose surface may be able to affect the phenotypic properties of cells that are on that surface, with smooth surfaces supporting a more chondrocytic phenotype. In addition, wells made from 1% agarose were able to prevent construct buckling potentially, due to their higher compliance.