3D-printed biodegradable polycaprolactone rib implants with tissue-specific mechanical properties promote chest wall recovery by stimulating tissue fibrosis

ABSTRACTHere we developed a tripartite biodegradable rib implant with tissue-specific mechanical properties by employing polycaprolactone and a dual-structure-reinforced selective laser sintering (SLS) strategy. Computational simulation revealed that the tripartite rib implant, with a 9 mm diameter load-bearing structure, exhibited a rib-like three-point bending stiffness of 31.3 N/mm, can withstand a maximum force of 121.5 N, and restore similar respiration movements of natural ribs. The modified SLS enabled the fabrication of the as-designed rib implants with improved mechanical properties while maintaining structural fidelity compared to conventional SLS, and their mechanical properties were validated through three-point bending, impact, and flexural fatigue testing. The 3D-printed biodegradable tripartite rib implant effectively prevented abnormal breathing and significantly improved the chest wall's morphological and physiological functions in a large-scale canine rib defect model. This exploration provides a promising approach to engineer biodegradable rib implants with tissue-specific mechanical properties for the long-term repair of chest wall defects.