A ¹⁸F radiolabelled Zn(ii) sensing fluorescent probe

Area of Science:

• Analytical Chemistry
• Biomedical Imaging
• Organic Chemistry

Background:

• Zinc(II) ions play crucial roles in biological processes.
• Dysregulation of zinc homeostasis is implicated in diseases like cancer.
• Development of selective and sensitive probes for zinc(II) is essential for research and diagnostics.

Purpose of the Study:

• To synthesize and characterize a novel fluorescent probe, AQA-F, for selective detection of zinc(II).
• To evaluate the probe's performance in terms of spectral response, binding affinity, and quantum yield enhancement.
• To assess the probe's utility for imaging endogenous zinc(II) in vitro in prostate and prostate cancer cell lines and its potential for dual-modal imaging.

Main Methods:

• Synthesis of the AQA-F fluorescent probe.
• Spectroscopic analysis (emission shift, quantum yield determination) upon zinc(II) binding.
• Binding studies to determine the dissociation constant (Kd) for zinc(II).
• In vitro testing in prostate and prostate cancer cell lines.
• Radiosynthesis of [18F]AQA-F for potential PET imaging.

Main Results:

• AQA-F demonstrated selective fluorescence detection of zinc(II) with a ratiometric emission shift of up to 80 nm.
• Significant enhancement of quantum yield from 4.2% to 35% upon zinc(II) binding.
• A binding constant (Kd) of 15.2 µM was determined for zinc(II).
• The probe successfully responded to endogenous zinc(II) levels in vitro in prostate and prostate cancer cells.
• [18F]AQA-F was synthesized with 8.6% radiochemical yield and 97% purity in 88 minutes.

Conclusions:

• AQA-F is a highly selective and sensitive fluorescent probe for zinc(II) detection.
• The probe exhibits favorable photophysical properties and strong binding affinity for zinc(II).
• AQA-F shows significant potential as a dual-modal (fluorescence/PET) imaging agent for studying zinc(II) in biological systems, particularly in cancer research.