Un échafaudage plat et pliable inspiré de l'origami pour l'ostéogenèse par distraction

Congenital limb-length asymmetry and major bone loss after trauma or tumour resection can cause lasting disability and secondary musculoskeletal complications. Distraction osteogenesis restores bone length and integrity but often requires prolonged treatment. We developed an origami-inspired flat-foldable scaffold (OIFFS) for implantation in the initial osteotomy gap that deploys during distraction, aiming to support bone regeneration and shorten consolidation. Scaffolds were fabricated in modular form from polycaprolactone (PCL) containing 4 wt% hydroxyapatite (HA) by injection moulding. Fabrication fidelity was assessed by micro-computed tomography (micro-CT) through comparison with the original CAD design. Modules were assembled into continuous configurations, and their mechanical performance was evaluated using a semi-physiological loading protocol reproducing compression for implantation, daily elongation during distraction, and partial weight bearing during consolidation. In vitro cytocompatibility was evaluated by encapsulating MG-63 osteoblast-like cells within a gelatin methacryloyl (GelMA) hydrogel in direct contact with scaffold. Cell viability was assessed after three days using Live/Dead fluorescence staining and confocal microscopy. Micro-CT analysis showed a mean geometric deviation of less than 50 µm from the intended design. The assembled modular scaffolds remained structurally intact after compressed by 70%, to 30% of their initial height and completed the semi-physiological loading protocol without failure. After three days, confocal imaging showed that most MG-63 cells encapsulated within GelMA remained viable. Short cytoplasmic extensions were observed, suggesting early cell spreading and interaction with the surrounding hydrogel. These findings demonstrate the feasibility of a high-fidelity modular scaffold that withstands loading representative of distraction osteogenesis while providing a cytocompatible environment that supports early cell spreading. OIFFS is designed for implantation at the initial osteotomy and deployment with the developing gap, potentially supporting bone regeneration throughout distraction and reducing treatment time.