A Step Toward an NIR-Emitting ESIPT Probe for Smart Zn²⁺ Sensing in Different Environments

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Current zinc ion (Zn²⁺) sensors often rely on photoinduced electron transfer (PET), which primarily alters fluorescence intensity without significant spectral shifts.
• Developing sensors with distinct spectral responses is crucial for improved detection and imaging.

Purpose of the Study:

• To develop a novel near-infrared (NIR) fluorescent sensor for Zn²⁺ detection.
• To couple the photoinduced electron transfer (PET) mechanism with excited state intramolecular proton transfer (ESIPT) for enhanced sensing capabilities.

Main Methods:

• Development of a NIR fluorescent probe by integrating PET and ESIPT mechanisms.
• Characterization of the sensor's response to Zn²⁺ binding, focusing on emission spectral changes.
• Evaluation of the sensor's utility for in vitro and in vivo Zn²⁺ imaging.

Main Results:

• The developed sensor exhibits two well-separated emission bands (λ_em ≈ 540 and 770 nm) upon binding with Zn²⁺.
• The ratio of these emission bands is highly sensitive to the probe's environment, indicating effective Zn²⁺ detection.
• The sensor demonstrates potential for both in vitro and in vivo imaging of Zn²⁺.

Conclusions:

• A novel NIR fluorescent sensor based on coupled PET-ESIPT mechanisms has been successfully developed for Zn²⁺ detection.
• This sensor provides a sensitive and responsive tool for monitoring Zn²⁺.
• The findings offer advanced capabilities for imaging Zn²⁺ in biological systems, aiding in the study of zinc's biological functions.