Characterizing the Mechanical Properties of 3D Printed Structures for Growth Plate Tissue Engineering

Stem cell differentiation is highly sensitive to the biochemical and mechanical environment. A major concern in tissue engineering is the need of a robust technique for producing structures with the precise amount of rigidity to guide stem cell differentiation. Damaged cartilage within the physis does not regenerate easily and can lead asymmetric growth arrest, making it an ideal model application. The physis has three distinct zones where cells evolve differently depending on the environmental conditions. Previous in vivo rabbit studies indicate that the mechanical properties of the 3D printed structures implanted in this area have an effect on stem cell differentiation in the area. In this work we use a solvent solution consisting of a multifunctional acrylate-based resin and ethanol to control the overall modulus of the structure. 3D printed pillar structures of varying solvent concentrations and backfills (air and a poly(ethylene glycol) diacrylate based hydrogel ) were put through compression testing and we found that there was an apparent reduction in the modulus of higher concentrations of the solvent solution of over 30 percent. This work allows us to control the modulus of 3D printed structures, which can be applied to future stem cell differentiation studies.