Unveiling in Vivo Subcutaneous Thermal Dynamics by Infrared Luminescent Nanothermometers

TLDR

Recent core/shell engineering of rare‑earth doped luminescent nanoparticles has opened a new era in fluorescence thermal biosensing, enabling minimally invasive experiments in living cells and small animal models. The study evaluates the use of active‑core/active‑shell Nd³⁺‑ and Yb³⁺‑doped nanoparticles as subcutaneous thermal probes. These nanoprobes function in the infrared transparency window of biological tissues, allowing deep temperature sensing through temperature‑dependent emission spectra that provide a ratiometric readout. In vivo subcutaneous thermal relaxation monitoring with the injected core/shell nanoparticles demonstrated the technique’s potential as a diagnostic tool for small animals.

Abstract

The recent development of core/shell engineering of rare earth doped luminescent nanoparticles has ushered a new era in fluorescence thermal biosensing, allowing for the performance of minimally invasive experiments, not only in living cells but also in more challenging small animal models. Here, the potential use of active-core/active-shell Nd3+- and Yb3+-doped nanoparticles as subcutaneous thermal probes has been evaluated. These temperature nanoprobes operate in the infrared transparency window of biological tissues, enabling deep temperature sensing into animal bodies thanks to the temperature dependence of their emission spectra that leads to a ratiometric temperature readout. The ability of active-core/active-shell Nd3+- and Yb3+-doped nanoparticles for unveiling fundamental tissue properties in in vivo conditions was demonstrated by subcutaneous thermal relaxation monitoring through the injected core/shell nanoparticles. The reported results evidence the potential of infrared luminescence nanothermometry as a diagnosis tool at the small animal level.