3D-Printed Region-Specific Biomimetic Prosthesis for Enhancing Heterogeneous Double-Interface Integration of Bone-Prosthesis and Tendon-Prosthesis.

Large bone defects with loss of natural tendon and soft tissue attachment sites remain challenging in prosthetic reconstruction because both bone-prosthesis and tendon-prosthesis interface integration must be achieved. To address this heterogeneous dual-interface requirement, this study proposes and validates a 3-dimensional printed (3D-printed) region-specific biomimetic titanium alloy prosthesis design strategy. This strategy integrates biomimetic tendon ordered microstructures and biomimetic trabecular-like disordered porous structures within distinct functional regions of the same Ti6Al4V prosthesis. Specifically, the top cap was designed with tendon-like ordered microstructures for soft tissue attachment, whereas the body region was designed with trabecular porous structures for bone integration. In vitro experiments demonstrate that the biomimetic tendon structure markedly promotes the directional alignment and tenogenic differentiation of tendon-derived stem cells, while the biomimetic trabecular-like structure favors osteogenic differentiation and mineralization maturation of bone-marrow-derived mesenchymal stem cells. In vivo animal experiments further validate that a single structure is insufficient to simultaneously meet the dual demands of soft tissue attachment and bone stability. In contrast, the 3D-printed region-specific biomimetic prosthesis establishes spatially partitioned microenvironments for tendon and bone formation in vivo, enabling more coordinated heterogeneous double-interface tissue integration.