Biomimetic meniscal scaffold: achieving high-fidelity fabrication through optimization of 3d printing path and stacking pattern

The meniscus is an important tissue structure within the human body, but lacks the ability to regenerate and repair itself. Existing extrusion-based 3D printing technologies face significant challenges in precisely controlling filament deposition and structural deformation to create biomimetic meniscal scaffolds with high precision, due to the mismatch between the print head motion and path design. Therefore, it is urgent to optimize the 3D printing technology to accurately reproduce the meniscus structure in terms of fan-shaped morphology and gradient porosity. In this work, a high-fidelity biomimetic meniscal scaffold was constructed by designing the optimal print path and pattern stacking method. A hydrogel was formulated using gelatin, sodium alginate, methylcellulose and hydroxyapatite, and the modulation of its printability by physical and chemical crosslinking as well as the personalized design of the printing process were investigated. For filament buildup, a regulation scheme for printing speed in the corner was proposed, which reduced the pore area error of horizontal surface by about 30%. The repetitive stacking scheme with variable layer height achieved successful reproduction of all horizontal pores. A sector scaffold with a double trapezoidal cross-section consisting of radial and annular infill patterns was designed and printed, with an overall dimensional accuracy of ~ 90% and Young’s modulus of up to 39.24 kPa, which effectively reproduced the morphology and mechanical characteristics of the meniscus tissue. In addition to the introduction of a feasible printing methodology for the reproduction of meniscus structures, this study also highlights the significance of morphology mimicry in advancing tissue engineering, which provides a universal platform for future functional studies and clinical translation of bioprinted meniscal implants.