Bioderived, 3D-Printable, and Biocompatible Polycarbonate/Hydroxyapatite Composite Scaffolds

Regenerative strategies for bone repair would benefit from scaffolds that are mechanically resilient and biologically compatible. We present a fully bioderived and 3D-printable composite scaffold that meets these requirements while offering environmental sustainability through the integration of CO2-derived eugenol polycarbonate, bioderived cross-linkers, and hydroxyapatite (HAp) reinforcement. This scaffold exhibits excellent thermal stability (Tg ≥ 60 °C and Td ≥ 350 °C) and robust mechanical properties (flexural modulus ∼ 2.54 GPa and compressive modulus ∼ 220 MPa), aligning with the mechanical properties of human trabecular bone and outperforming reported polymer/HAp composites. It demonstrates exceptional creep resistance (∼0.82% strain under 3 MPa for 24 h), ensuring long-term mechanical integrity under physiological loads. A UV-assisted direct ink writing (DIW) technique, followed by post-UV curing, fabricates precise 3D structures that support cell attachment. The hydrophilicity of the scaffold is tunable via surface modifications to optimize cell-material interactions. In vitro cytocompatibility studies using MC3T3 preosteoblasts show >91% viability. Under simulated physiological conditions (PBS, 37 °C), the scaffold shows negligible mass loss over 18 weeks. Compared to conventional 3D-printed scaffolds that rely on petrochemical feedstocks and exhibit weaker mechanical resilience, this sustainable system offers a compelling combination of printability, mechanical robustness, and biocompatibility with potential for advanced bone regenerative therapies.