Single cell temperature probed by Eu+ 3 doped TiO2 nanoparticles luminescence
Garvas, M., Acosta, S., Urbančič, I., Koklič, T., Štrancar, J., Nunes, L. A., ... & Bittencourt, C.
luminescence, nanoparticles, synchrotron radiation, TiO2
Temperature is a critical parameter in biology, affecting the speed of reactions that occur in living systems. Nevertheless, measuring temperature with subcellular resolution (micrometric scale) and reliability remains a challenge to overcome. In this perspective, luminescence nanothermometry is a non-contact technique which aims to measure temperature with a sub-micrometric spatial resolution through the use of nanomaterials whose luminescence is affected solely by changes in temperature. Here, TiO2 nanoparticles doped with Eu+3 ions (Eu+3-TiO2) are used for sensing temperature differences within single living cells. XRD, XPS, SEM, TEM and NEXAFS analysis allow the determination of the physicochemical characteristics of the Eu+3-TiO2 nanoparticles and, the variation of the luminescence intensity of the Eu+3-TiO2 nanoparticles with their temperature is investigated. The successful internalization of Eu+3-TiO2 nanoparticles in different types of cells is observed. The luminescence of nanoparticles internalized in L929 fibroblast cells is measured when the system is heated in a biological relevant temperature range. Making use of an appropriate calibration curve the temperature variation inside the cells is determined with sensitivity of 0.5 K per 1% of luminosity change when heated.