A highly sensitive acidic pH fluorescent probe and its application to HepG2 cells

Area of Science:

• Chemical Biology
• Molecular Imaging
• Biotechnology

Background:

• Intracellular pH (H+) is a critical regulator of cellular functions.
• Accurate monitoring of acidic organelles requires sensitive and specific probes.
• Existing probes may lack sufficient sensitivity, photostability, or cell permeability.

Purpose of the Study:

• To design, synthesize, and characterize a novel fluorescent probe for intracellular H+ imaging.
• To evaluate the probe's performance in terms of sensitivity, photostability, and pH dependence.
• To demonstrate the probe's utility in visualizing acidic organelles within living cells.

Main Methods:

• Synthesis and characterization of a novel rhodamine-based fluorescent probe.
• pH titration to determine the probe's pKa and fluorescence response.
• In vitro evaluation of probe sensitivity, photostability, and cell membrane permeability.
• Fluorescent imaging of HepG2 cells to monitor intracellular H+.

Main Results:

• The novel probe exhibits a 100-fold increase in fluorescence intensity between pH 4.2-6.0.
• The probe has a pKa of 4.85, suitable for studying acidic organelles.
• Demonstrated high sensitivity, good photostability, and excellent cell membrane permeability.
• Successful fluorescent imaging of intracellular H+ in HepG2 cells.

Conclusions:

• The developed fluorescent probe is effective for optical imaging of intracellular H+.
• The probe's properties make it valuable for studying acidic organelles in living cells.
• This tool offers significant potential for advancing research in cellular pH dynamics.