La³⁺/Sr²⁺ Dual-Substituted Hydroxyapatite Nanoparticles as Bone Substitutes: Synthesis, Characterization, In Vitro...

The present study aims to synthesize biocompatible and bioactive lanthanum (La³⁺)/strontium (Sr²⁺) dual ion doped hydroxyapatite (HA) nanomaterials by sol-gel method. The discrete substitution of La³⁺ and Sr²⁺ in pure HA enhances the osteoconductivity. The co-substitution of various La³⁺ concentrations (0.03, 0.06 and 0.1 M) regulates the physical and In Vitro properties. The study also investigates the effect of La³⁺/Sr²⁺ substituents on the crystalline property, microstructure, photoluminescence and In Vitro bioactivity of HA samples. La³⁺/Sr²⁺ co-substitution decreases the crystallite size of HA without any significant distortion of the crystal structure. In addition, the dual ions doping influences nanoparticles morphology by reducing the particle size from 75 to 20 nm. The In Vitro bioactivity tests for the La³⁺/Sr²⁺ co-substituted HA confirm the osteoconductive boneapatite generating capacity. Bactericidal tests against Staphylococcus aureus and Pseudomonas aeruginosa stains show better resistivity of La³⁺/Sr²⁺-HA samples. To authenticate the biocompatibility and antimicrobial activity of the synthesized La³⁺/Sr²⁺ dual doped HA nanoparticles for bone implant applications, different tests like cell viability and toxicity were conducted using human lung A549 cells.