Development of a Composite Based on Hydroxyapatite, Carboxymethyl Cellulose, and Boron Nitride Nanotubes As a Potential Material for Bone Graft

Treating large or load-bearing bone defects remains a significant clinical challenge as conventional calcium phosphate ceramics, although biocompatible and osteoconductive, lack the fracture resistance required to match the performance of bone. The present work addresses this gap by developing a multifunctional composite that integrates hydroxyapatite (HA), carboxymethyl cellulose (CMC), and boron nitride nanotubes (BNNT). The strategy leverages HA’s bioactivity, CMC’s processability, and BNNT’s exceptional mechanical reinforcement to overcome the intrinsic brittleness of pure HA. The prepared composite exhibited remarkable mechanical improvements, with a 185% increase in Vickers hardness and a 1200% enhancement in fracture toughness, achieving values comparable to cortical bone. Biological evaluation confirmed the material’s noncytotoxicity in nontumor cell assays, demonstrating its safety for biomedical use. These results highlight the composite’s potential as a durable, high-performance bone graft substitute for critical bone repair applications.