Pyrolytic Carbon Microlattices from 3D‐Printed Polyethylene Glycol Diacrylate and their In Vitro Assessment for Bone Regeneration

This study investigates the potential of 3D pyrolytic carbon (PyC) scaffolds, derived from 3D‐printed polyethylene glycol diacrylate (PEGDA) lattices, for bone tissue engineering. The pyrolytic conversion of PEGDA is systematically studied, which shows that the pyrolysis temperature significantly influences the structural and material properties of the resulting PyC materials. The scaffolds exhibit tunable electrical conductivity and mechanical strength, with the conductivity increasing by seven orders of magnitude as the pyrolysis temperature rises from 500 to 900 °C. Similarly, mechanical properties improve with temperature, reaching a maximum elastic modulus of 36.87 ± 2.95 GPa and hardness of 5.4 ± 0.42 GPa at 900 °C. The 3D PyC microlattices support MC3T3‐E1 preosteoblast proliferation and promote osteogenic differentiation, as evidenced by the expression of key markers (ALP, Runx2, OCN, and Col1A1). Among the scaffolds, PyC obtained at 500 °C shows the highest metabolic activity attributed to their oxygen‐rich surface chemistry, while those treated at 900 °C induce the most robust differentiation, driven by enhanced stiffness and mechanotransductive signaling. These findings position 3D‐printed PyC scaffolds as promising, tunable platforms for bone tissue regeneration, combining structural integrity with cell‐instructive properties.