ENGINEERING HARD-SOFT TISSUE INTERFACES VIA 3D PRINTING AND MELT ELECTROWRITING

Hard-soft tissue interfaces, such as tendon-to-bone or cartilage-to-bone connections, are critical for musculoskeletal function. These interfaces exhibit gradual transitions in architecture, mechanics, composition, and biochemical signaling over micro- to nano-scale dimensions, making them challenging to regenerate after injury and difficult to replicate in laboratory conditions. In our studies, we aim to closely mimic the gradient structure of native hard-soft tissue interfaces using advanced biofabrication techniques. By employing 3D printing and melt electrowriting, we strive to create biomimetic gradient structures with precise control over material deposition at the micrometer scale. We designed graded and smooth transitional scaffolds with controlled architecture and material composition, followed by cell seeding with different cell types. The constructs were cultured under both static and dynamic conditions, including cyclic mechanical stretching, to assess their impact on cell behavior and tissue formation. Our findings demonstrate that the substrate designs and mechanical stimulation significantly influence cellular responses (Figure 1). Tenocytes responded distinctly to cyclic mechanical loading, showing enhanced proliferation and alignment, while osteoblasts exhibited a less pronounced response to mechanical cues. These observations highlight the importance of mechanical microenvironments in directing cell fate at tissue interfaces. Our study paves the way for gradient-functional scaffold design, facilitating the engineering of complex, hierarchical, and heterogeneous tissue interfaces. The combination of melt electrowriting, 3D printing and mechanical stimulation offers a promising approach to recapitulating native tissue gradients, ultimately contributing to improved strategies for orthopedic regeneration. For any figures or tables, please contact the authors directly.