Excited-State-Altering Ratiometric Fluorescent Probes for the Response of β-Galactosidase in Senescent Cells

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Biology

Background:

• Beta-galactosidase (β-Gal) is a key biomarker for diseases linked to cellular senescence.
• Accurate detection and spatial mapping of β-Gal activity are crucial for disease investigation.

Purpose of the Study:

• To develop novel fluorescent sensors for ratiometric detection of β-Gal activity.
• To investigate the mechanism of enzyme-responsive optical shifts using DFT calculations.

Main Methods:

• Synthesis of two excited-state-altering responsive fluorescent sensors (TF1 and TF2) based on tricyanofuran (TCF) and naphthol units.
• Ratiometric detection of β-Gal activity in PBS solution and senescent A549 cells.
• Density functional theory (DFT) calculations to elucidate excited-state transitions.

Main Results:

• TF1 and TF2 sensors exhibit quenched fluorescence quenched by β-Gal.
• Significant ratiometric optical shifts (absorption ~475 nm to 630 nm, fluorescence ~660 nm) upon β-Gal hydrolysis.
• High sensitivity and selectivity for β-Gal detection in biological samples and senescent cells.

Conclusions:

• Developed fluorescent sensors provide a framework for multimodal optical probes.
• The sensors are effective tools for senescence studies, diagnostic assay development, and therapeutic assessment.
• Modulating excited-state properties offers a pathway for designing advanced optical probes.