Bioceramic and Antimicrobial Metal Oxide Reinforced Nanocomposites for Maxillofacial Bone Fixation

This study develops third-generation poly(lactic acid) (PLA) nanocomposites with tailored degradation, osteoconductivity, and mechanical properties to address the issue of metallic maxillofacial implants, eliminating secondary removal surgeries while providing superior biocompatibility and reducing stress shielding. Hydroxyapatite (HAP), bioceramic-natural-bone-mimicking eggshell-derived nanoparticles (ESNP), and antimicrobial metal oxides (TiO₂ and ZnO) were synthesized using wet chemical precipitation, ball milling, sol-gel, and hydrothermal techniques, respectively, and incorporated into PLA matrices to develop PLA/ES (PE), PLA/HAP (PH), PLA/ES/TiO₂ (PET), PLA/HAP/TiO₂ (PHT), PLA/ES/ZnO (PEZ), and PLA/HAP/ZnO (PHZ) using solvent casting. Structural and compositional analyses of the synthesized nanomaterials and composites were performed using Fourier Transform Infrared Spectroscopy (FT-IR), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Field-Emission Scanning Electron Microscopy (FE-SEM). Mechanical testing revealed that PE and PH composites achieved tensile strengths of 48.66 ± 1.27 MPa and 52.71 ± 0.45 MPa, tensile moduli of 1.94 ± 0.03 GPa and 2.14 ± 0.13 GPa, and Shore D hardness of 79.29 ± 1.31 SHN and 81.25 ± 0.90 SHN, respectively. The incorporation of NPs not only improved surface roughness (2.53 μm) and enhanced hydrophilicity (∼65°) but also exhibited increased biodegradation rates (PEZ: 14.83 ± 0.49%, PHZ: 10.48 ± 0.35% over 9 weeks). Cytocompatibility evaluations using osteoblast (MG-63) cells confirmed ≥ 80% cell viability, with hemolysis rates ≤ 2.82%, demonstrated enhanced osteoconductivity through improved cell adhesion and proliferation, and superior antibacterial activity for the composites containing metal oxides, highlighting their potential suitability for low-load-bearing zones of the maxillofacial region (maxilla and zygoma) implants.