Integration of 3D Fluorescence Imaging and Luminescent Thermometry with Core–Shell Engineered NaYF4:Nd3+/Yb3+/Ho3+ Nanoparticles

• Published in: Inorganic chemistry Vol. 63; no. 4; pp. 1840 - 1852
• Main Authors: Vinícius-Araújo, Marcus, Shrivastava, Navadeep, Silva Loures, Guilherme, Krause, Rafael Freire, Sousa, Marcelo Henrique, de Santana, Ricardo Costa, Bakuzis, Andris Figueiroa
• Format: Journal Article
• Language: English
• Published: American Chemical Society 29-01-2024
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c03410

The design of rare-earth-doped upconversion/downshifting nanoparticles (NPs) for theoretical use in nanomedicine has garnered considerable interest. Previous research has emphasized luminescent nanothermometry and photothermal therapy, while three-dimensional (3D) near-infrared (NIR) luminescent tracers have received less attention. Our study introduces Nd3+-, Yb3+-, and Ho3+-doped NaYF4 core–shell luminescent NPs as potential multiparametric nanothermometers and NIR imaging tracers. Nd3+ sensitizes at 804 nm, while Yb3+ bridges to activators Ho3+. We evaluated the photoluminescence properties of Nd3+-, Yb3+-, and Ho3+-doped core and core–shell NPs synthesized via polyol-mediated and thermal decomposition methods. The NaYF4:NdYbHo­(7/15/3%)@NaYF4:Nd­(15%) core–shell NPs demonstrate competitive nanothermometry capabilities. Specifically, the polyol-synthesized sample exhibits a sensitivity of 0.27% K–1 at 313 K (40 °C), whereas the thermally decomposed synthesized sample shows a significantly higher sensitivity of 0.55% K–1 at 313 K (40 °C) in the near-infrared range. Control samples indicate back energy transfer processes from both Yb and Ho to Nd, while Yb to Ho energy transfer enhances Ho3+-driven upconversion transitions in green and red wavelengths, suggesting promise for photodynamic therapy. Fluorescence molecular tomography confirms 3D NIR fluorescence nanoparticle localization in a biological media after injection, highlighting the potential of core–shell NPs as NIR luminescent tracers. The strategy’s clinical impact lies in photothermal treatment planning, leveraging core–shell NPs for (pre)­clinical applications, and enabling the easy addition of new functionalities through distinct ion doping.