A Ratiometric and near-Infrared Fluorescent Probe for Imaging Cu²⁺ in Living Cells and Animals

Area of Science:

• Chemical Biology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Copper ions (Cu²⁺) play critical roles in biological processes.
• Dysregulation of Cu²⁺ is linked to various diseases, necessitating precise detection methods.
• Existing detection methods often lack sensitivity, selectivity, or in vivo applicability.

Purpose of the Study:

• To rationally construct a novel ratiometric and near-infrared fluorescent probe for Cu²⁺.
• To evaluate the probe's performance in terms of sensitivity, selectivity, and response range.
• To demonstrate the probe's utility for fluorescence imaging of Cu²⁺ in biological systems.

Main Methods:

• Synthesis of a novel ratiometric fluorescent probe (NIR-Cu) utilizing a tricarbocyanine chromophore.
• Characterization of the probe's photophysical properties and response to Cu²⁺.
• In vitro and in vivo fluorescence imaging experiments in cells and mice.

Main Results:

• The developed probe NIR-Cu exhibited a ratiometric fluorescent response to Cu²⁺.
• A large emission wavelength shift (up to 142 nm) in the far-red to near-infrared region was observed.
• High sensitivity and selectivity for Cu²⁺ detection were achieved, with a significant fluorescence ratio change (I₆₃₆/I₇₇₈).

Conclusions:

• The novel NIR-Cu probe is effective for ratiometric detection of Cu²⁺.
• The probe demonstrates excellent sensitivity and selectivity for Cu²⁺.
• NIR-Cu is suitable for fluorescence imaging of Cu²⁺ in living cells and mice, offering a valuable tool for biological research.