An optical nanofibre-enabled on-chip single-nanoparticle sensor

Area of Science:

• Optics and Photonics
• Nanotechnology
• Microfluidics

Background:

• Single-nanoparticle detection is crucial for fundamental physics and biological applications.
• Existing methods often face limitations in sensitivity and throughput.
• Microfluidic devices offer precise control over sample handling at the microscale.

Purpose of the Study:

• To develop and demonstrate an optical nanofiber-enabled microfluidic sensor for nanoparticle detection and sizing.
• To achieve label-free, high-throughput analysis of nanoparticles in solution.
• To explore the sensor's potential for biological applications, including virus detection.

Main Methods:

• Utilizing the evanescent field of an optical nanofiber for nanoparticle scattering detection.
• Employing a microfluidic channel to confine nanoparticles to a femtoliter detection volume.
• Real-time monitoring of transmitted light intensity changes caused by nanoparticle interaction.
• Statistical analysis of scattering signals for nanoparticle size determination.

Main Results:

• Successful detection and sizing of individual polystyrene nanoparticles down to 100 nm.
• Distinguishing between mixtures of nanoparticles with different sizes (200, 500, 1000 nm).
• Demonstrated high-throughput counting of yeast cells and dual-wavelength detection of fluorescent nanoparticles.
• Exosomes in solution were successfully detected.

Conclusions:

• The optical nanofiber microfluidic sensor enables sensitive, label-free detection and sizing of nanoparticles.
• The system demonstrates high throughput and potential for multiplexed sensing.
• This technology holds promise for rapid detection of diverse viruses and other biological analytes.