Innovative prospects in 3D printed bio-scaffolds for osteochondral tissue engineering: A systematic review

Background: Advancements in 3D printing technologies have significantly transformed osteochondral tissue engineering, enabling the creation of scaffolds that closely mimic the structural and biological complexities of native tissue. These scaffolds provide a 3D environment conducive to cellular adhesion, proliferation, and differentiation while maintaining critical mechanical and biodegradable properties. Aim: To explore the feasibility of 3D printed scaffolds in osteochondral applications, highlights innovative materials and techniques, and addresses the existing knowledge gaps and challenges in clinical translation. Methods: This scoping review adhered to PRISMA extension for scoping reviews guidelines to systematically map innovations in 3D printed bio-scaffolds for osteochondral tissue engineering. Due to heterogeneous data, it favored a scoping over systematic or meta-analytic approaches. The review aimed to identify innovations in scaffold materials, fabrication techniques, and translational strategies. Key questions addressed bioprinting methods, scaffold designs, and translational challenges. Studies included were in English, peer-reviewed, and focused on 3D printed scaffolds for osteochondral repair. Exclusions were nonosteochondral, non-3D fabrication studies, grey literature, editorials, and non-English papers. Literature was sourced from six databases using comprehensive keywords and Boolean operators. Backward citation tracking added relevant studies; no date limits were applied. Screening followed a four-phase selection process with dual independent reviewers. Data were charted thematically without bias assessment, focusing on methods, outcomes, and future gaps. Results: The fabrication of biomimetic scaffolds, incorporating bioactive elements such as growth factors, has shown promise in replicating the extracellular matrix and enhancing tissue regeneration. Cutting-edge techniques, including inkjet, extrusion-based, and laser-assisted bioprinting, allow precise spatial control and multi-material integration essential for osteochondral scaffolds. Innovations such as graded scaffolds and bio-inks enriched with nanoparticles have further improved scaffold functionality, mechanical stability, and biological activity. Despite these advancements, limitations persist, including material challenges in achieving the desired balance of bioactivity, biodegradability, and mechanical properties. Fabrication methods face issues of scalability, reproducibility, and resolution, while the long-term biological interactions between scaffolds and host tissues, particularly degradation products, remain underexplored. Regulatory and economic barriers also impede clinical translation, underscoring the need for collaborative research efforts. Future directions emphasize the potential of emerging technologies, such as 4D printing, smart biomaterials, and soundwave patterning, to address current challenges and unlock new opportunities. Conclusion: The convergence of biomaterial science, additive manufacturing, and regenerative medicine holds immense promise for advancing personalized treatments and revolutionizing osteochondral tissue engineering.