Low-Affinity Zinc Sensor Showing Fluorescence Responses with Minimal Artifacts.

Area of Science:

• Chemical Biology
• Biophysical Chemistry
• Neuroscience

Background:

• Understanding zinc biology necessitates molecular probes with precise zinc affinity.
• Existing probes often lack specificity or are affected by environmental factors like pH and other metal ions.

Purpose of the Study:

• To develop a low-affinity zinc probe with high specificity for accurate zinc bioimaging.
• To investigate the photophysical properties and mechanisms enabling probe selectivity.
• To demonstrate the probe's utility in complex biological systems.

Main Methods:

• Design and synthesis of a novel low-affinity zinc probe (HBO-ACR) using an azacrown ether and a benzoxazole fluorophore.
• Steady-state and transient photophysical investigations to elucidate probe response mechanisms.
• Zinc bioimaging experiments using human cancer cells (PANC-1) and rodent neurons in cultures and acute brain slices.

Main Results:

• The HBO-ACR probe exhibits a fluorescence turn-on response to high zinc levels.
• The probe demonstrates high tolerance to pH variations and interference from other transition-metal ions.
• Successful zinc bioimaging was achieved in PANC-1 cells and rodent hippocampal neurons, validating its utility.

Conclusions:

• Incorporating positively charged ionophores is a valid strategy for creating low-affinity probes for biometal visualization.
• The HBO-ACR probe offers a valuable tool for studying zinc's role in biological processes.
• This approach enhances the development of selective probes for essential trace elements in biological research.