Label-Free Imaging of Single Nanoparticles Using Total Internal Reflection-Based Leakage Radiation Microscopy

Area of Science:

• Nanotechnology
• Microscopy
• Environmental Science

Background:

• Label-free, fast, single nanoparticle detection is essential for monitoring environmental nano-pollutants.
• Nano-pollutants pose potential toxic risks to human health.

Purpose of the Study:

• To present a label-free imaging method for single nanoparticles using total internal reflection (TIR)-based leakage radiation microscopy.
• To demonstrate the capability of imaging polystyrene (PS) and gold (Au) nanospheres.

Main Methods:

• Utilized total internal reflection (TIR) based leakage radiation microscopy.
• Imaged single polystyrene (PS) and gold (Au) nanospheres (down to 100 nm and 30 nm, respectively).
• Confirmed leakage radiation by comparing far-field imaging with simulated near-field electric field distribution.

Main Results:

• Successfully imaged single PS and Au nanospheres with high resolution.
• Demonstrated localized enhancement and interference of TIR evanescent waves.
• Showcased imaging of PS nanospheres with varying incident polarizations.

Conclusions:

• TIR-based leakage radiation microscopy enables fast, label-free, in situ imaging of single nanoparticles.
• This technique is a competitive alternative for nano-pollutant monitoring.
• The method provides insights into nanoparticle interactions and optical properties.