Surface state-controlled C-dot/C-dot based dual-emission fluorescent nanothermometers for intra-cellular thermometry

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Fluorescence-based nanothermometers offer precise, non-contact temperature measurement capabilities.
• Developing accurate and sensitive optical thermometers is crucial for various scientific and medical applications.

Purpose of the Study:

• To fabricate a dual-emission temperature sensing platform using carbon dots (CDs) for optical thermometry.
• To investigate the temperature-dependent fluorescence response of the fabricated nanothermometer.
• To demonstrate the application of the nanothermometer for visual intracellular temperature measurement.

Main Methods:

• Fabrication of a dual-emission platform via electrostatic self-assembly of oppositely charged fluorescent CDs.
• Characterization of the platform's fluorescence properties in response to temperature variations (15-85 °C).
• Evaluation of the nanothermometer's sensitivity, reproducibility, and biocompatibility for in-vitro applications.

Main Results:

• The platform exhibits two emission centers (blue at 440 nm and orange at 590 nm).
• Orange fluorescence intensity changes with temperature (15-85 °C), while blue fluorescence remains stable.
• A visible color change from orange to blue indicates temperature shifts, with a sensitivity of 0.93%/°C.
• Temperature affects the surface states of orange-emissive CDs, not the blue-emissive ones.

Conclusions:

• The developed C-dot based dual-emission nanospheres serve as a reliable optical nanothermometer.
• The platform allows for naked-eye observation of temperature changes and accurate intracellular thermometry.
• The nanothermometer demonstrates excellent biocompatibility and stability for biological applications.