Development and Characterization of Hardystonite-Based 3D-Printed Scaffolds for Bone Tissue Engineering

Bone tissue plays a critical role in providing structural support, protecting vital internal organs, and maintaining mineral homeostasis. However, its limited self-healing capability necessitates prompt and effective interventions for treating injuries or defects. Currently, bone grafting remains the most common treatment approach, but it is hindered by significant drawbacks, such as donor shortages and infection risks. To overcome these challenges, bone tissue engineering (BTE) has emerged as a promising alternative. BTE focuses on designing and developing porous scaffolds that mimic the mechanical and biological properties of natural bone tissue, facilitating regeneration and integration. Scaffolds are central to BTE, as they provide a temporary framework for cell attachment, proliferation, and tissue formation while supporting nutrient and waste exchange. To succeed in bone regeneration, scaffolds must possess specific characteristics, including controlled porosity, adequate mechanical strength, and bioactivity to promote new bone tissue formation. Recent advances in scaffold materials and fabrication methods have enabled the creation of highly functional structures tailored to biological needs. In this study, hardystonite-based scaffolds were fabricated using an emulsion of preceramic polymers, with additive manufacturing techniques employed to shape the material. Hardystonite (Ca₂ZnSi₂O₇) is particularly suitable for BTE due to its excellent biocompatibility, bioactivity, and mechanical properties. Specifically, the Direct Ink Writing (DIW) 3D printing method was used, allowing precise control over scaffold geometry and porosity, which are crucial for biological applications. To investigate the impact of composition on scaffold performance, two types of inks were prepared: one containing boric anhydride and one without. The study evaluated how these compositions influenced scaffold performance and assessed the effects of varying water content in both ink formulations. Water content was adjusted to 28%, 38%, and 43% to analyze its impact on the bioactivity and mechanical properties of the scaffolds. This approach is vital for understanding how compositional changes and water content variations affect scaffold functionality in bone tissue regeneration. A primary goal of these hardystonite-based scaffolds is to promote the formation of hydroxyapatite (HA), a major component of natural bone. Upon implantation, the controlled release of ions such as calcium (Ca²⁺) and silicate ((SiO₄)⁴⁻) from the scaffold interacts with the biological environment, encouraging HA deposition. This process forms a mineral layer similar in composition to natural bone, which is essential for scaffold mineralization and integration with surrounding tissue. By combining advanced materials like hardystonite with innovative fabrication techniques, this research aims to address current limitations in bone regeneration strategies and contribute to the development of effective solutions in bone tissue engineering. The results highlight the potential of hardystonite-based scaffolds as a robust platform for bone repair, offering favorable structural and mechanical properties. This work underscores the feasibility of using advanced bioceramic materials in regenerative medicine, paving the way for novel therapeutic solutions to treat severe bone damage.