Real-time intracellular temperature imaging using lanthanide-bearing polymeric micelles

Abstract

Measurement of thermogenesis in individual cells is a remarkable challenge due to the complexity of the biochemical environment (such as pH and ionic strength) and to the rapid and yet not well-understood heat transfer mechanisms throughout the cell. Here, we present a unique system for intracellular temperature mapping in a fluorescence microscope (uncertainty of 0.2 K) using rationally designed luminescent Ln3+-bearing polymeric micellar probes (Ln = Sm, Eu) incubated in breast cancer MDA-MB468 cells. Two-dimensional (2D) thermal images recorded increasing the temperature of the cells culture medium between 296 and 304 K shows inhomogeneous intracellular temperature progressions up to ∼20 degrees and subcellular gradients of ∼5 degrees between the nucleolus and the rest of the cell, illustrating the thermogenic activity of the different organelles and highlighting the potential of this tool to study intracellular processes. ; This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by Portuguese funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. Financial support from the project (NanoHeatControl, POCI-01-0145-FEDER-031469), funded by FEDER, through POCI and by Portuguese funds (OE), through FCT/MCTES, by European Union's Horizon 2020 FET Open program under grant agreement nos. 801305 and 829162, Spanish Ministry of Science Innovation and Universities (grant no: PGC2018_095795_B_I00) and Diputación General de Aragón (E11/17R) are acknowledged. ANCN thanks SusPhotoSolutions project, CENTRO-01-0145-FEDER-000005, Portugal, for his grant. The authors acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. ; Peer reviewed