Cellular detection of a mitochondria targeted brominated vinyl triphenylamine optical probe (TP‐Br) by X‐ray fluorescence microscopy

Abstract

Triphenylamine (TP) derivatives such as two‐branch cationic vinylbenzimidazolium triphenylamine TP−2Bzim are promising turn‐on fluorescent probes suitable for two‐photon imaging, labelling mitochondria in live cells. Here, we designed two TP−2Bzim derivatives as bimodal probes suitable for X‐ray fluorescence imaging. The conjugation of the TP core with a rhenium tricarbonyl moiety in the TP−RePyta probe altered the localisation in live cells from mitochondria to lysosomes. The introduction of bromine on the TP core generated the TP−Br probe retaining good photophysical properties and mitochondria labelling in live cells. The influence of calcium channels in the uptake of TP−Br was studied. Synchrotron Radiation X‐ray Fluorescence (SXRF) imaging of bromine enabled the detection of TP−Br and suggested a negligible presence of the probe in an unbound state in the incubated cells, a crucial point in the development of these probes. This study paves the way towards the development of TP probes as specific organelle stainers suitable for SXRF imaging.