Fluorogenic Heterodimers Enable Rapid Fluorescence Lifetime Imaging of Prostate-Specific Membrane Antigen-Positive...

Area of Science:

• Biomedical Engineering
• Organic Chemistry
• Oncology

Background:

• Accurate prostate cancer margin delineation is critical to prevent recurrence.
• Current fluorescence-guided surgery (FGS) probes have limitations like high background noise or slow activation.
• Prostate-specific membrane antigen (PSMA) is a target for FGS in prostate cancer.

Purpose of the Study:

• To develop a novel strategy for rapidly activatable NIR probes for PSMA-targeted FGS.
• To create probes with enhanced fluorescence properties and fast activation kinetics.
• To evaluate the efficacy of these probes in real-time imaging for prostate cancer surgery.

Main Methods:

• Developed a modular design using fluorogenic heterodimers for rapid NIR fluorescence activation.
• Synthesized and optimized environment-sensitive cyanine-based fluorophores (e.g., Cy1a).
• Conjugated a PSMA-targeting ligand to create the activatable probe Cy2a.

Main Results:

• The optimal fluorophore Cy1a showed a 120-fold fluorescence enhancement.
• Cy2a demonstrated rapid, PSMA-binding-dependent fluorescence activation and extended fluorescence lifetime (0.16 to 1.01 ns).
• Cy2a enabled real-time, PSMA-specific imaging in live cells and achieved high tumor-to-background contrast in tissues and animal models.

Conclusions:

• Established a versatile strategy for creating fast-activatable NIR probes.
• Demonstrated Cy2a's potential for precise, real-time imaging in prostate cancer surgery.
• The fluorescence lifetime-based analysis offers spatial resolution of probe-target interactions.