Dynamic Micromechanical Characterization of 3D Printed Bone In Vitro Models Manufactured via Vat Photopolymerization

Abstract

3D in vitro organotypic bone models enable the study of human cells in an environment that mimics in vivo physiology and mechanobiology. However, creating large bone tissue scaffolds (≈1 cm3) with fine feature sizes (≈200–400 µm) and interconnected porosity is not feasible at scale using traditional stochastic techniques. Thus, this study aimed to manufacture porous 3D scaffold geometries using a novel, osteoconductive resin via vat photopolymerization and analyze their ability to mimic the in vivo bone micromechanical environment. Scaffolds (n = 85) are printed with 80% porosity using an ESOA-PEDGA. Resin After static culture with murine NIH 3T3 fibroblasts, the scaffolds are assessed to characterize print fidelity, proliferation behavior, and mechanical properties. After printing, each scaffold type closely resembled its targeted geometry. Uniform cell distribution is observed in all geometries during initial seeding, with significantly more cells throughout each scaffold after 7 days. Mechanical testing revealed the presence of cells, not just media, has a significant impact on stiffness for all geometries. Only Voronoi geometries have a significant increase in storage moduli during culture. These results confirm scaffold geometry is a critical factor affecting cell distribution, proliferation, and scaffold stiffness, which has significant implications for bone tissue-engineered scaffolds.