Ultrabright fluorescent nanothermometers.

Area of Science:

• Nanotechnology
• Optical Thermometry
• Materials Science

Background:

• Accurate nanoscale temperature measurement is critical for understanding biological processes.
• Existing thermometry methods often lack the resolution or sensitivity required for 3D nanoscale applications.

Purpose of the Study:

• To develop novel ultrabright fluorescent nanothermometers for precise 3D temperature measurements at the nanoscale.
• To demonstrate the capability of these nanothermometers in relevant environments like hydrogels.

Main Methods:

• Utilizing Förster resonance energy transfer (FRET) between encapsulated dyes (rhodamine 6G and rhodamine B) within silica nanothermometers.
• Exciting dyes with a single wavelength (488 nm) and measuring temperature via the ratio of fluorescence intensities.
• Validating measurements using numerical simulations and demonstrating single nanothermometer usage.

Main Results:

• Achieved ultrabright fluorescent nanothermometers (∼50 nm) with brightness equivalent to hundreds of dye molecules.
• Demonstrated repeatable temperature measurements with uncertainty down to 0.4 K and sensitivity of ∼1%/K (20-50 °C).
• Successfully mapped accurate 3D temperature distributions in a hydrogel using these nanothermometers.

Conclusions:

• Ultrabright fluorescent nanothermometers offer a powerful new tool for nanoscale thermometry.
• The technology shows significant promise for advanced biomedical applications requiring precise temperature monitoring.
• High brightness and sensitivity enable accurate 3D temperature mapping even with limited numbers of nanothermometers.