Rational design of a red-emission fluorescent probe for imaging mitochondrial viscosity and fatty liver tissues

Abnormal mitochondrial viscosity is closely associated with various diseases. Thus, it is imperative to design and synthesized fluorescent probes for monitoring changes in mitochondrial viscosity. In this work, two series of fluorescence probes with triphenylamine unit and 2-hydroxyphenylbenzothiazole unit respectively were constructed. The impact of varying chain lengths on the photophysical properties of these probes was investigated. The results indicated that probe TPAC12 with dodecane group exhibited the largest fluorescence enhancement. The results of cell imaging experiments demonstrated that all these probes exhibited specific targeting towards mitochondria and were not influenced by changes in mitochondrial membrane potential. Additionally, probe TPAC12 facilitated the monitoring of viscosity alterations within mitochondria. Importantly, probe TPAC12 has been effectively utilized for the identification of both fatty liver and normal liver tissues. These results suggested that probe TPAC12 holds great potential as a valuable tool for detecting mitochondrial viscosity in biological systems.