Combined Temperature and Pressure Sensing Using Luminescent NaBiF ₄:Yb,Er Nanoparticles

The current status of the use of nanoparticles for photothermal treatments is reviewed in detail. The different families of heating nanoparticles are described paying special attention to the physical mechanisms at the root of the light-to-heat conversion processes. The heating efficiencies and spectral working ranges are listed and compared. The most important results obtained in both in vivo and in vitro nanoparticle assisted photothermal treatments are summarized. The advantages and disadvantages of the different heating nanoparticles are discussed.

Acquiring the temperature of a single living cell is not a trivial task. In this paper, we devise a novel nanothermometer, capable of accurately determining the temperature of solutions as well as biological systems such as HeLa cancer cells. The nanothermometer is based on the temperature-sensitive fluorescence of NaYF(4):Er(3+),Yb(3+) nanoparticles, where the intensity ratio of the green fluorescence bands of the Er(3+) dopant ions ((2)H(11/2) --> (4)I(15/2) and (4)S(3/2) --> (4)I(15/2)) changes with temperature. The nanothermometers were first used to obtain thermal profiles created when heating a colloidal solution of NaYF(4):Er(3+),Yb(3+) nanoparticles in water using a pump-probe experiment. Following incubation of the nanoparticles with HeLa cervical cancer cells and their subsequent uptake, the fluorescent nanothermometers measured the internal temperature of the living cell from 25 degrees C to its thermally induced death at 45 degrees C.