A Polarity Sensitive Turn-On NIR Fluorescent Probe for Wash-Free Cell Imaging

Area of Science:

• Chemical Biology
• Molecular Imaging
• Biotechnology

Background:

• Wash-free fluorescent probes simplify bioimaging by reducing steps and potential errors.
• Donor-π-acceptor (D-π-A) molecules with twisted intramolecular charge transfer (TICT) character show unique photophysical properties.

Purpose of the Study:

• To design and synthesize a novel wash-free fluorescent probe for high-contrast bioimaging.
• To develop a water-soluble derivative of a D-π-A molecule with environmentally sensitive emission.

Main Methods:

• Synthesis of a D-π-A fluorescent molecule (TB-PY) and its water-soluble derivative (TBPYS).
• Investigation of TBPYS's solvatochromism and polarity-responsive fluorescence.
• Application of TBPYS for wash-free cell imaging in Hep-G2 cells.

Main Results:

• TBPYS exhibits environmentally sensitive near-infrared (NIR) emission, quenched in aqueous media and turned on in low-polarity environments.
• The probe effectively distinguishes between hydrophobic cytoplasm and aqueous extracellular environments in live cells.
• High contrast imaging was achieved with a signal-to-noise ratio of 16, demonstrating wash-free capabilities.

Conclusions:

• TBPYS is a practical and efficient fluorescent probe for wash-free bioimaging.
• The probe's polarity-responsive NIR emission enables high-contrast visualization of cellular compartments.
• This work highlights the potential of TBPYS in simplifying and improving bioimaging techniques.