TICT-Based Near-Infrared Ratiometric Organic Fluorescent Thermometer for Intracellular Temperature Sensing.

Area of Science:

• Biomedical Engineering
• Materials Science
• Chemical Biology

Background:

• Near-infrared (NIR) fluorescent thermometers are vital for high-resolution intracellular temperature visualization.
• Understanding cellular temperature is key to investigating cellular functions and biochemical activities.

Purpose of the Study:

• To design and synthesize a novel donor-Π-acceptor luminogen (TBB) for temperature-sensitive NIR emission.
• To construct a ratiometric fluorescent thermometer using TBB and Rhodamine 110 encapsulated in F127 polymer nanoparticles (TRF NPs).

Main Methods:

• Suzuki coupling reaction was employed to synthesize the TBB luminogen.
• TBB and Rhodamine 110 were encapsulated into an amphiphilic polymer matrix F127 to form TRF NPs.
• Ratiometric fluorescence measurements were used to evaluate temperature sensitivity and reversibility.

Main Results:

• The synthesized TBB exhibited twisted intramolecular charge transfer-based NIR emission, aggregation-induced emission, and temperature-sensitive properties.
• TRF NPs demonstrated a temperature sensitivity of 2.37%·°C⁻¹, a wide response range (25–65 °C), and excellent reversibility.
• Intracellular thermometry successfully monitored temperature changes (25–53 °C) in Hep-G2 cells during photothermal therapy.

Conclusions:

• TRF NPs function as effective ratiometric fluorescent thermometers for biological applications.
• The developed nanoparticles show significant potential for real-time intracellular thermometry, particularly in photothermal therapy monitoring.
• This work highlights the utility of NIR-emitting luminogens for advanced bioimaging and diagnostics.