# meso-Dimethylaminonaphthyl-BODIPY Derivatives as Bioimaging Probes to Monitor Intracellular pH and Label Lysosomes and Lipid Droplets

## TL;DR

This paper introduces new BODIPY-based fluorescent probes that can track pH changes and label lysosomes and lipid droplets in living cells.

## Contribution

The novel contribution is the development of BODIPY derivatives with dual functionality for pH monitoring and organelle labeling in live cells.

## Key findings

- The BODIPY derivatives selectively labeled lysosomes and lipid droplets in HeLa cells without cytotoxicity.
- BODIPY 3 showed a 192.5% fluorescence increase with decreasing pH from 7.0 to 4.5, indicating strong pH sensitivity.
- Computational studies confirmed solvent-dependent spectral shifts and matched experimental absorption data.

## Abstract

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.