Luminescent lanthanide-doped calcium phosphate from oyster shell waste: an example of bright recycling Puentedura-Navarro, Paula Fernández Penas, Raquel Acebedo Martínez, Francisco Javier Fernández Sánchez, Jorge Fernando Gómez-Morales, Jaime This work has been performed in the framework of the project “Advanced materials using biogenic calcium carbonate from seashell waste (CASEAWA), Ref. PCI2020-112108 funded by MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR”. PCI2020-112108 is part of the ERA-NET Cofund BlueBio Programme (H2020) supported by the European Union. We also acknowledge projects GBRMat (ref. 2023-151538NB-100, MCIU/AEI, Spain) and ARCHER (MUR-M4C2 I1.2 of PNRR with ID project no. MSCA_0000008, Italy). AF was supported by Ministero della Sanità RF-2018- 12366471 and Compagnia San Paolo Trapezio No 68155. This research explores the transformation of biogenic CaCO3 microparticles (Ø < 45 μm) from oyster shell waste into luminescent Eu- or Tb-doped calcium phosphate (apatites), using a sustainable “one-step” and eco-friendly method. The full transformation was achieved at 200 °C via a dissolution–precipitation mechanism. Precipitates were composed of Eu- or Tb-doped apatite particles, with average sizes L = 163 ± 7 nm and anisometric shapes for the former, and 41 ± 8 nm and more isometric shapes for the latter. Alongside these, particles of either EuPO4·nH2O or TbPO4·nH2O (rhabdophane) were present. The physicochemical and electrokinetic analysis revealed the A- and B-carbonate substitutions and labile CO32− species in the apatite particles, and ζ-potentials approaching zero in the aqueous suspensions at physiological pH levels, indicating a tendency for particle aggregation. The luminescence properties, such as relative luminescent intensity and luminescence lifetimes, were dependent on the lanthanide content and the presence of the rhabdophane phase. The Ap–Ln samples demonstrated cytocompatibility, with cell viability exceeding 85% when incubated with murine pancreatic endothelial cells (MS1) and murine mesenchymal stem cells (m17.ASC), regardless of the lanthanide type or the particle dosage used (ranging from 0.1 to 100 μg mL−1). 2025-02-24T08:52:29Z 2025-02-24T08:52:29Z 2025-01-21 journal article Puentedura-Navarro, Paula et al. Luminescent lanthanide-doped calcium phosphate from oyster shell waste: an example of bright recycling. CrystEngComm, 2025,27, 1078-1089. https://doi.org/10.1039/D4CE01217H https://hdl.handle.net/10481/102615 10.1039/D4CE01217H eng info:eu-repo/grantAgreement/EC/H2020/PCI2020-112108 http://creativecommons.org/licenses/by-nc/4.0/ open access Atribución-NoComercial 4.0 Internacional Royal Society of Chemistry