A novel fluorescent probe with a large Stokes shift targeting lysosomes and lipid droplets and its application to cellular imaging

Lipid droplets and lysosomes are crucial organelles that play significant roles in cellular metabolism. Therefore, studying both lipid droplets and lysosomes simultaneously holds great value. A new fluorescent probe BTD-Lyso was designed based on the principle of intramolecular charge transfer (ICT). The probe was formed with a typical D-π-A structure, and it used benzothiadiazole as the electronic acceptor and morpholine as the electronic donor. The experimental results showed that BTD-Lyso was able to detect the change of polarity in the microenvironment. Furthermore, the probe showed a large Stokes shift (300 nm), excellent selectivity, polarity sensitivity, and photostability. In addition, it could be successfully utilized in cellular imaging due to its low cytotoxicity and could target lipid droplets and lysosomes well.