Novel two-photon fluorescent probe with high fluorescence quantum yields for tracking lipid droplets in biological systems.

Abstract

Lipid droplets (LDs) played an important role in storing neutral lipids process. In this work, we developed a series of fluorescent dyes PIE1-PIE4 with high fluorescence quantum yields based on a single phenanthrenequinone imidazole fluorophore core. Among these compounds, we introduced diethyl aniline group on the phenanthrenequinone imidazole core to provide the compound PIE1. It is firstly found that PIE1 could real-color image and track lipid droplets (LDs) in living cells. However, we modified nitrile, imidazole and methyl group on the same fluorophore core to afford three dyes PIE2, PIE3 and PIE4, respectively. Although PIE2, PIE3 and PIE4 possessed high fluorescence quantum yields in various organic solvents, they could not real-color image and track LDs in living cells.