A mitochondrial targeting fluorescent probe based on the covalently linked anti-inflammatory drug dexamethasone and Cy7

As one of the most important organelles, mitochondria not only produces energy but is also involved in cell metabolism and many pathological processes. Thus, targeting and monitoring mitochondria is of great importance. In this study, a commonly utilized anti-inflammatory drug, dexamethasone (Dex), whose action position is mitochondria, was employed as a mitochondrial targeting functional group, and a near-infrared fluorescent dye, Cy7, was covalently linked with Dex to form Cy7-Dex, for fluorescent visualization of mitochondria. The corresponding Cy5-Dex and Cy3-Dex were synthesized in control experiments to explore the effects of different cyanine groups on the parent drug of Dex. Although all these Dex derivatives can fluorescently visualize mitochondria, different enzyme hydrolysis results and anti-inflammatory effects can be observed among them, thereby illustrating that different fluorophores might induce different effects on the properties of the same parent drug. Thus, only the appropriate fluorophore can be utilized to modify the drug to avoid false conclusions. (C) 2017 Elsevier B.V. All rights reserved.