Abstract

Objective: Lipid droplets (adiposomes) are cellular organelles with distinguish structure and functions that play significant role in energy homeostasis and lipotoxicity and oxidative stress prevention, therefore represent a desirable target for fluorescent labeling. In this work, we proposed a number of new fluorogenic compounds—arylidene-rhodanines and their acyclic analogues – substances that label lipid droplets due to structural fragments responsible for the appearance of fluorescence in a lipophilic environment. Methods: The target arylidene-rhodanines and their acyclic analogues were obtained using modified literature methods of Knoevenagel condensation, the optical properties of the resulting compounds in a standard set of solvents were studied and then the most promising substances were tested as fluorescent dyes on Hela Kyoto cells using widefield microscopy. Discussion: We discovered that the derivatives containing a 2,5-dimethoxybenzylidene fragment or similar groups are characterized by a noticeable variation in fluorescence quantum yield depending on the environment properties. Cellular labeling of such compounds was studied. We showed that incubation of Hela Kyoto cells with substances (In) and (III) led to fluorescence appearance in the BFP channel, associated with the location of lipid droplets detected in the cells when visualized in transmitted light. Conclusions: As a result, we found that two obtained compounds—dimethoxybenzylidene-rhodanine and dimethoxybenzylidene-malononitrile – can be used as selective fluorogenic dyes for lipid droplets labeling in live Hela Kyoto cells under widefield fluorescent microscopy conditions.