Single cell temperature probed by Eu⁺³ doped TiO₂ nanoparticles luminescence

Abstract

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.

Ion-induced bias in Ag2S luminescent nanothermometers

“…[2][3][4][5][6] LNThs have been used for diagnosis of tumors, 7,8 diagnosis of affections of the circulatory and nervous systems, 9,10 monitoring of inflammation events and even in studies of single cells. [11][12][13] Despite the great results and the variety of LNThs reported, luminescence thermometry is being questioned. 14,15 This is because of biases that cast doubts on the reliability of the thermal readouts provided by LNThs.…”