Quantum dot thermometry evaluation of geometry dependent heating efficiency in gold nanoparticles

Area of Science:

• Nanotechnology and Biomedical Engineering
• Materials Science
• Optical Physics

Background:

• Gold nanoparticles (AuNPs) exhibit localized surface plasmon resonance (LSPR) tunable by morphology.
• Photothermal (PT) properties of AuNPs are crucial for applications like cancer therapy and diagnostics.
• Efficient PT agents require high absorption and heating efficiency at specific wavelengths.

Purpose of the Study:

• To investigate the absorption and heating efficiency of various gold nanoparticle morphologies.
• To determine the optimal AuNP geometry for photothermal applications within the first biological window (808 nm).
• To identify AuNPs with high absorption cross-section per unit mass for efficient photothermal conversion.

Main Methods:

• Utilized quantum dot-based thermometry for precise temperature measurements.
• Employed double beam confocal microscopy to monitor heating dynamics.
• Synthesized and characterized gold nanorods, nanocages, nanoshells, and nanostars with LSPR at 808 nm.

Main Results:

• Heating efficiency was strongly dependent on nanoparticle geometry.
• Gold nanorods and long-edge gold nanostars demonstrated near 100% heating efficiency.
• Gold nanorods and nanocages exhibited the highest absorption cross-section per unit mass.

Conclusions:

• Nanoparticle morphology significantly impacts photothermal efficiency.
• Gold nanorods and nanocages are optimal photothermal agents due to their high absorption and heating efficiencies.
• These findings suggest potential for reduced metal loading in biomedical applications.