Hydrothermal Transformation of Eggshell Calcium Carbonate into Apatite Micro-Nanoparticles: Cytocompatibility and Osteoinductive Properties

The eggshell is a biomineral consisting of CaCO3 in the form calcite phase and pervading organic matrix (1–3.5 wt.%). Transforming particles into calcium phosphate (apatite) micro-nanoparticles opens door to repurposing waste as materials with potential biomedical applications, fulfilling principles circular economy. Previous methods obtain these consisted mainly two steps, first one involving calcination eggshell. In this research, direct transformation by one-pot hydrothermal method ranging from 100–200 °C was studied, using suspensions stoichiometric P/CaCO3 ratio, K2HPO4 P reagent, eggshells (Ø < 50 μm) both untreated treated NaClO remove surface matter. group, complete conversion achieved at 160 °C, most displayed hexagonal plate morphology, eventually central hole. replacement occurred 180 yielding granular (spherulitic) apatite nanoparticles. were cytocompatible when incubated MG-63 human osteosarcoma cells m17.ASC murine mesenchymal stem promoted osteogenic differentiation cells. study results are useful for designing fabricating biocompatible microstructured osteoinductive properties applications bone tissue engineering dentistry.