A red-emissive D-A-D type fluorescent probe for lysosomal pH imaging

Area of Science:

• Cell Biology
• Chemical Biology
• Biochemistry

Background:

• Lysosomes are vital organelles involved in cellular functions and disease.
• Monitoring lysosomal pH is crucial for understanding cellular processes and pathology.
• Existing methods for lysosomal pH detection have limitations.

Purpose of the Study:

• To develop a novel fluorescent probe for sensitive and visual detection of lysosomal pH.
• To characterize the photophysical properties and pH response of the probe.
• To demonstrate the probe's utility in live cell imaging and monitoring autophagy.

Main Methods:

• Rational design and synthesis of a donor-acceptor-donor (D-A-D) fluorescent probe (DBTD).
• Spectroscopic characterization of DBTD's response to pH changes.
• In vitro calibration of the probe's linear pH response range and pKa determination.
• Live-cell imaging experiments in SGC-7901 cells to assess lysosomal pH.
• Application of the probe to visualize pH changes during autophagy.

Main Results:

• DBTD exhibits a unique D-A-D structure with red emission centered at 614 nm.
• The probe shows a sensitive and linear response to pH in the range of 4.5–5.2, with a pKa of 5.0.
• DBTD accurately monitors lysosomal pH variations in SGC-7901 cells.
• The probe successfully images pH changes in lysosomes during autophagy.

Conclusions:

• DBTD is a highly effective fluorescent probe for lysosomal pH detection.
• Its properties make it suitable for real-time imaging of lysosomal pH dynamics.
• DBTD holds significant potential as a tool for studying lysosome-related biological processes and diseases.