Label-free detection of single nanoparticles with disordered nanoisland surface plasmon sensor

Area of Science:

• Nanotechnology
• Surface Science
• Optics

Background:

• Surface plasmon polaritons (SPPs) are light-driven electron oscillations on metal surfaces.
• Disordered metallic nanoisland substrates offer unique optical properties for sensing applications.
• Detecting single nanoparticles is crucial for various fields, including diagnostics and materials science.

Purpose of the Study:

• To develop a novel sensing method for individual nanoparticles.
• To utilize surface plasmon polaritons (SPPs) and speckle patterns for nanoparticle detection.
• To demonstrate the capability of detecting gold nanoparticles and polystyrene beads.

Main Methods:

• Fabrication of disordered metallic nanoisland substrates.
• Excitation and detection of surface plasmon polaritons (SPPs).
• Analysis of speckle patterns from scattered SPPs for nanoparticle detection.
• Verification using bright-field and fluorescence imaging.

Main Results:

• Speckle patterns from scattered SPPs act as a unique fingerprint of the sensor surface microstructure.
• Experimental measurement of speckle decorrelation enabled detection of single nanoparticle sorption.
• Successful detection of individual gold nanoparticles and polystyrene beads was achieved.

Conclusions:

• Sensing of single nanoparticles is feasible using disordered metallic nanoisland substrates and SPP leakage radiation.
• Speckle pattern analysis provides a sensitive and label-free method for nanoparticle detection.
• This approach offers a promising platform for advanced nanoscale sensing applications.