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.

The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches 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.

No abstract

Luminescence nanothermometry requires standardization for reliable and quantitative evaluation.

The tremendous development of nanotechnology is bringing us closer to the dream of clinical application of nanoparticles in photothermal therapies of tumors. This requires the use of specifi c nanoparticles that must be highly biocompatible, effi cient light-to-heat converters and fl uorescent markers. Temperature reading by the heating nanoparticles during therapy appears of paramount importance to keep at a minimum the collateral damage that could arise from undesirable excessive heating. In this work, this thermally controlled therapy is possible by using Nd 3+ ion-doped LaF 3 nanocrystals. Because of the particular optical features of Nd 3+ ions at high doping concentrations, these nanoparticles are capable of in vivo photothermal heating, fl uorescent tumor localization and intratumoral thermal sensing. The successful photothermal therapy experiments here presented highlight the importance of controlling therapy parameters based on intratumoral temperature measurements instead of on the traditionally used skin temperature measurements. In fact, signifi cant differences between intratumoral and skin temperatures do exist and could lead to the appearance of excessive collateral damage. These results open a new avenue for the real application of nanoparticle-based photothermal therapy at clinical level.

In this study, we report on the remarkable two-photon excited fluorescence efficiency in the "biological window" of CaF(2):Tm(3+),Yb(3+) nanoparticles. On the basis of the strong Tm(3+) ion emission (at around 800 nm), tissue penetration depths as large as 2 mm have been demonstrated, which are more than 4 times those achievable based on the visible emissions in comparable CaF(2):Er(3+),Yb(3+) nanoparticles. The outstanding penetration depth, together with the fluorescence thermal sensitivity demonstrated here, makes CaF(2):Tm(3+),Yb(3+) nanoparticles ideal candidates as multifunctional nanoprobes for high contrast and highly penetrating in vivo fluorescence imaging applications.

In this work, we report the multifunctional character of neodymium-doped LaF₃ core/shell nanoparticles. Because of the spectral overlap of the neodymium emission bands with the transparency windows of human tissues, these nanoparticles emerge as relevant subtissue optical probes. For neodymium contents optimizing the luminescence brightness of Nd³⁺:LaF₃ nanoparticles, subtissue penetration depths of several millimeters have been demonstrated. At the same time, it has been found that the infrared emission bands of Nd³⁺:LaF₃ nanoparticles show a remarkable thermal sensitivity, so that they can be advantageously used as luminescent nanothermometers for subtissue thermal sensing. This possibility has been demonstrated in this work: Nd³⁺:LaF₃ nanoparticles have been used to provide optical control over subtissue temperature in a single-beam plasmonic-mediated heating experiment. In this experiment, gold nanorods are used as nanoheaters while thermal reading is performed by the Nd³⁺:LaF₃ nanoparticles. The possibility of a real single-beam-controlled subtissue hyperthermia process is, therefore, pointed out.