Mechanically reinforced core-shell scaffold with integrated structure and function for accelerated tendon repair

Core-shell scaffold designs that mimic the biophysical structure of tendon extracellular matrix offer unique advantages for tendon repair. However, balancing the structural integrity of the scaffold with the desired material and biological properties remains challenging, limiting the effectiveness of the scaffold. Here, we present a new method for fabricating a core-shell scaffold with tailored properties for tendon tissue engineering. The scaffold core, designed for cell guidance, was created using direct ink writing, resulting in a helically interconnected fibre structure with controllable anisotropy and pore sizes. The mechanically reinforced shell, produced through uniaxial cold stretching of a laser-drilled sheet, featured microsurface ridges and through-hole arrays. The core-shell integration enabled sequential degradation and mechanical properties aligned with tendon tissue requirements, providing extended structural support and improved space for neotissue ingrowth. In vitro and in vivo studies confirmed the scaffold's non-cytotoxicity and superior tendon matrix regeneration, with increased collagen deposition and structural alignment compared to controls. These findings highlight the potential of the developed scaffold for advancing tendon repair applications.