Multifunctional Response of Chitosan-Based Hydroxyapatite-Potassium Sodium Niobate Composite Scaffolds for Bone...

The development of multifunctional scaffolds integrating mechanical robustness and bioactivity is crucial for bone tissue engineering. In this study, chitosan-based scaffolds reinforced with hydroxyapatite (HAP) and potassium sodium niobate (KNN) are fabricated via freeze-drying. Structural characterization confirmed crystalline phase purity, strong interfacial bonding, and uniform elemental distribution without secondary phases. Morphological analysis of the composites revealed interconnected porous networks with an average pore size of 95 ± 8 nm and porosity of 77%. Mechanical testing depicted marked improvement, with the Young's modulus of the composite reaching 4.14 MPa, nearly double that of chitosan. Bioactivity assays demonstrated dense apatite growth after 12 days in simulated body fluid, with a Ca/P ratio of 1.66, close to stoichiometric HAP. Swelling and enzymatic degradation studies indicated reduced fluid uptake and slower degradation of 11.9 ± 0.4% over 24 days for the composite, compared to pure chitosan and single-phase scaffolds, thereby confirming enhanced stability. Antioxidant analysis using an in vitro assay reported 48.6 ± 0.5% radical scavenging for the composite, notably higher than 36 ± 0.6% observed for chitosan, while protein adsorption increased to 20-27 µg/mL compared to 9 µg/mL. MG-63 osteoblasts exhibited > 90% viability at day 1 and sustained growth through day 5 with spreading and adhesion. These results highlight HAP-KNN reinforced chitosan scaffolds as promising multifunctional platforms for orthopedic applications.