Sensitive Conjugated-Polymer-Based Fluorescent ATP Probes and Their Application in Cell Imaging

Area of Science:

• Materials Science
• Biotechnology
• Analytical Chemistry

Background:

• Conjugated polyelectrolytes (CPEs) are versatile materials with tunable optical properties.
• Adenosine triphosphate (ATP) is a crucial biomarker in biological systems.
• Developing efficient and specific probes for ATP detection and cell imaging remains a challenge.

Purpose of the Study:

• To design and synthesize novel cationic conjugated polyelectrolytes (CPEs) based on a poly(p-phenylene ethynylene terthiophene) backbone.
• To investigate the spectroscopic properties and aggregation behavior of these CPEs in different solvents.
• To evaluate the potential of these CPEs as fluorescent probes for cell imaging and ATP detection.

Main Methods:

• Synthesis of three CPEs (PPET3-N1, PPET3-N2, PPET3-N3) with varying side chain lengths.
• UV-vis absorption and fluorescence spectroscopy to study optical properties and solvent effects.
• Confocal fluorescence microscopy for cell imaging and localization studies.
• Evaluation of cytotoxicity and ATP-induced fluorescence quenching.

Main Results:

• The synthesized CPEs exhibited strong aggregation in aqueous solutions, indicated by changes in UV-vis and fluorescence spectra.
• Spectroscopic properties of the CPEs were sensitive to ATP, showing fluorescence quenching and red-shifted absorption.
• All CPEs localized on cell membranes and within cells, with enhanced staining correlating to longer side chains.
• PPET3-N2 demonstrated low cytotoxicity and efficient ATP-induced quenching, suggesting potential for in vivo applications.

Conclusions:

• The designed CPEs are effective fluorescent probes for cell membrane and intracellular imaging.
• The sensitivity of CPEs to ATP opens possibilities for developing biosensors for ATP detection.
• PPET3-N2 shows promise for quantitative cell imaging of ATP in biological systems.