A fabrication method using unconventional pattern designs to enhance the mechanical strength of 3D bio-printed PCL scaffolds.

Purpose: Cartilage tissue has a very limited self-repairing capacity due to its aneural and avascular nature, and current clinical strategies fail to consistently regenerate normal hyaline cartilage for effective chondrogenic repair. This study aims to explore the potential of 3D bioprinting, particularly through hybrid constructs of cell-embedded soft and synthetic materials, as a solution for enhancing the mechanical and biological properties of tissue-engineered scaffolds. Methods: We developed and implemented optimization protocols for melt-extrusion bioprinting to fine-tune mechanical properties by adjusting strand distance and pattern shapes. Gelatin methacryloyl (GelMA) and polycaprolactone (PCL) hybrid constructs were fabricated to investigate the synergy between materials in achieving improved mechanical strength while preserving biological compatibility. Results: The optimized printing parameters yielded scaffolds with compressive modulus values aligning closely with the target, demonstrating the clinical applicability of the method. The hybrid GelMA-PCL constructs exhibited enhanced mechanical properties and retained a high biological fraction, validating their potential for chondrogenic applications. Conclusion: This study presents an innovative approach to improving the mechanical strength of tissue-engineered constructs through architectural optimization. These findings represent a significant step toward advancing tissue-engineered cartilaginous products from laboratory research to clinical applications, addressing a critical challenge in cartilage repair.