Advancing bone bioprinting with nanoclay bioinks: from formulation to translation

Nanoclays have emerged as potent biomaterials for regenerative medicine, characterised by a unique disk-like morphology and a high surface-to-volume ratio, endowing them with inherent bioactivity. These mineral-based nanoparticles can modulate cellular signalling, making them particularly effective for directing osteogenic differentiation. While three-dimensional (3D) bioprinting has revolutionised the fabrication of complex tissue scaffolds, the primary bottleneck remains the development of bioinks that simultaneously provide high structural fidelity and a supportive microenvironment for cells. Consequently, nanoclay-based formulations have moved to the forefront of research, bridging this gap to provide ideal bioink candidates for bone tissue engineering (BTE). This review explores the application of nanoclay to prepare multibiofunctional nanocomposite bioinks, specifically BTE. It begins by providing a comprehensive overview of nanoclay characteristics and their biomedical applications, followed by a detailed analysis of nanoclay-based bioink formulations tailored for bone tissue constructs. It examines various bioprinting techniques and the use of different nanoclay types, emphasising their impact on bioink properties, including improved shear-thinning and enhanced mechanical strength, for bone tissue repair and regeneration. This review further presents the potential of optimised nanoclay-reinforced bioinks to advance bone tissue regeneration and facilitate successful clinical translation by critically evaluating current limitations and outlining future research directions.