An endoplasmic reticulum-selective ratiometric fluorescent probe for imaging a copper pool

Area of Science:

• Chemical Biology
• Molecular Imaging
• Biochemistry

Background:

• Copper ions play crucial roles in biological processes but their dysregulation is linked to various diseases.
• Developing selective and sensitive probes for copper ion detection is essential for understanding cellular copper homeostasis.
• Naphthalimide derivatives are widely explored as fluorescent probes due to their favorable photophysical properties.

Purpose of the Study:

• To develop a novel hydrazide-linked naphthalimide-based fluorescent probe for selective copper ion detection.
• To investigate the probe's biocompatibility and subcellular localization in live cells.
• To demonstrate the probe's utility in imaging copper accumulation in the endoplasmic reticulum (ER).

Main Methods:

• Synthesis and characterization of the hydrazide-linked naphthalimide probe (probe 1).
• Copper ion-selective hydrolysis studies and fluorescence spectroscopy.
• Live-cell imaging experiments using HeLa cells to assess probe localization and copper imaging capabilities.

Main Results:

• Probe 1 exhibited selective hydrolysis in the presence of copper ions, leading to a ratiometric fluorescence change.
• The probe demonstrated good biocompatibility and preferential localization to the endoplasmic reticulum in live HeLa cells.
• Successful imaging of copper accumulation within the ER of live cells was achieved using probe 1.

Conclusions:

• Hydrazide-linked naphthalimides can be designed as effective copper ion-selective fluorescent probes.
• Probe 1 is a promising tool for real-time monitoring of copper ion dynamics, particularly in the ER.
• This probe facilitates the study of cellular copper overload conditions and related biological implications.