A small molecule two-photon fluorescent probe for intracellular sodium ions

Area of Science:

• Chemical Biology
• Biomedical Imaging
• Molecular Probes

Background:

• Accurate monitoring of intracellular sodium ion (Na+) concentration is crucial for understanding various physiological processes.
• Existing methods for Na+ detection often face limitations in sensitivity, specificity, or applicability to live biological systems.
• Development of advanced fluorescent probes is essential for real-time, in situ analysis of Na+ dynamics.

Purpose of the Study:

• To develop and characterize a novel small-molecule two-photon fluorescent probe for sensitive and selective detection of Na+.
• To demonstrate the utility of the probe for real-time monitoring of intracellular Na+ ([Na+]i) fluctuations in live cells.
• To evaluate the probe's performance in imaging Na+ dynamics within living tissue at biologically relevant depths.

Main Methods:

• Synthesis and characterization of the small-molecule two-photon fluorescent probe (ANa2).
• Evaluation of the probe's photophysical properties, including two-photon excited fluorescence (TPEF) response to Na+.
• Cellular loading and validation of the probe for monitoring intracellular Na+ ([Na+]i) in live cells using fluorescence microscopy.
• In vivo imaging of Na+ dynamics in living tissue at depths exceeding 100 μm.

Main Results:

• The developed probe (ANa2) exhibits a strong TPEF enhancement in response to Na+ ions.
• ANa2 can be easily loaded into live cells, allowing for straightforward experimental application.
• The probe successfully enabled real-time monitoring of intracellular Na+ ([Na+]i) fluctuations in live cells.
• Effective imaging of Na+ dynamics was achieved in living tissue at depths greater than 100 μm.

Conclusions:

• ANa2 is a highly effective small-molecule two-photon fluorescent probe for Na+ detection.
• The probe facilitates easy loading into live cells and enables real-time monitoring of intracellular Na+.
• ANa2 demonstrates significant potential for deep-tissue imaging of Na+ dynamics in biological systems.