Work

Developing Upconversion (Yb3+–Er3+) and Downshifting (Yb3+–Ho3+–Er3+) PEG-Ylated Na3ZrF7 Degradable Nanoparticles as Ratiometric Luminescent Nanothermometers for Theranostic Applications

Year: 2025

Type: article

Abstract: In this work, we report the synthesis of Na 3 ZrF 7 nanoparticles as an appealing host matrix for lanthanide ions for both upconversion (bidoped, sensitizer-activator Yb 3+ –Er 3+ in the vis and NIR-I regions) and downshifting (tridoped, sensitizer-activator-activator Yb 3+ –Ho 3+ –Er 3+ in the NIR-II region) ratiometric luminescence nanothermometry in the physiological temperature range (293.15–323.15 K). We explored three different routes to reveal the most favorable synthetic approach for bioapplication purposes as well as investigated and characterized the temperature-dependent photoluminescence (PL) properties of the obtained nanoparticles. Furthermore, a biocompatible DSPE-PEG 2000 -based layer was incorporated to render the nanoparticles water-dispersible and to subsequently evaluate their degradation-induced in vitro toxicity toward HeLa and Normal Human Dermal Fibroblast (NHDF) cells. Additional in vitro tests were conducted to preliminarily evaluate the cellular uptake of the nanoparticles for future biological applications. We show that the synthetic conditions of the Na 3 ZrF 7 nanoparticles and the solvent environment influence their morphology, crystalline phase, and PL emission profiles. To the best of our knowledge, this is the first effort at an extensive systematic synthesis approach for nanosized core-only and core–shell(s) Na 3 ZrF 7 materials as ratiometric luminescent thermometers and the first reported temperature-sensing performance via Yb 3+ –Er 3+ (NIR-I-to-vis) upconversion and Yb 3+ –Ho 3+ –Er 3+ (NIR-I-to-NIR-II) downshifting mechanisms for this host material, both in cyclohexane and in an aqueous environment.

Source: ACS Applied Materials & Interfaces

DOI: 10.1021/acsami.5c02718