We report on Ytterbium and Neodymium codoped LaF₃ core/shell nanoparticles capable of simultaneous heating and thermal sensing under single beam infrared laser excitation. Efficient light-to-heat conversion is produced at the Neodymium highly doped shell due to non-radiative de-excitations. Thermal sensing is provided by the temperature dependent Nd³⁺ → Yb³⁺ energy transfer processes taking place at the core/shell interface. The potential application of these core/shell multifunctional nanoparticles for controlled photothermal subcutaneous treatments is also demonstrated.

The current status of the use of core–shell rare-earth-doped nanoparticles in biomedical applications is reviewed highlighting the most relevant advances.