meso-Dimethylaminonaphthyl-BODIPY Derivatives as Bioimaging Probes to Monitor Intracellular pH and Label Lysosomes...

Fluorescence-based probes are a powerful tool for monitoring living systems in real time with spatiotemporal precision. 3-Difluoroborodipyrromethene (BODIPY) derivatives are widely used as bioimaging probes due to their excellent photophysical properties, high quantum yields, and chemical stability. In this context, we report two BODIPY-based fluorescent probes for visualizing lysosomes and lipid droplets as well as tracking intracellular pH variations within living cells. Computational studies, employing molecular dynamics (MD) simulations and the simplified Tamm-Dancoff approximation (sTDA), were conducted to predict the absorption properties of these derivatives in different chemical environments. These studies accurately reproduced the experimental absorption bands and revealed solvent-dependent spectral shifts, providing insights into the photophysical behavior of the compounds. In vitro studies using HeLa cells demonstrated that the BODIPY derivatives effectively permeated the cell membrane and selectively labeled lysosomes and lipid droplets without causing cytotoxic effects. Furthermore, BODIPY 3 exhibited a significant fluorescence enhancement of 192.5% as the intracellular pH decreased from 7.0 to 4.5, confirming its potential as a bioimaging pH probe. Therefore, these results highlight the potential of these BODIPY derivatives as versatile fluorescence probes for investigating intracellular pH variations and organelle dynamics in living cells through fluorescence imaging.