%0 Journal Article
%T Fluorescence lifetime nanothermometer based on the equilibrium formation of anthracene AIE-excimers in living cells.
%A Ripoll C
%A Del Campo-Balguerías A
%A Alonso-Moreno C
%A Herrera-Ochoa D
%A Ocaña A
%A Martín C
%A Garzón-Ruíz A
%A Bravo I
%J J Colloid Interface Sci
%V 674
%N 0
%D 2024 Nov 15
%M 38925064
%F 9.965
%R 10.1016/j.jcis.2024.06.157
%X The effective measurement of temperature in living systems at the nano and microscopic scales continues to be a challenge to this day. Here, we study the use of 2-(anthracen-2-yl)-1,3-diisopropylguanidine, 1, as a nanothermometer based on fluorescence lifetime measurements and its bioimaging applications. In aqueous solution, 1 is shown in aggregated form and the equilibrium between the two main aggregate types (T-shaped and π-π) is highly sensitive to the temperature. The heating of the medium shifts the equilibrium toward the formation of highly emissive T-shaped aggregates. This species shows a high fluorescence emission and a long lifetime in comparison with the π-π aggregates and the freé monomer. A linear relationship between the fluorescence lifetime and the temperature both in aqueous solution and in a synthetic intracellular buffer was found. Fluorescence lifetime imaging microscopy (FLIM) also showed a linear relationship between lifetime and temperature with an excellent sensitivity in MCF7 breast cancer cells, which opens the door for its potential use as FLIM nanothermometer in the biomedical field.