Light-Induced Convective Segregation of Different Sized Microparticles

Area of Science:

• Microfluidics
• Nanotechnology
• Biophysics

Background:

• Particle sorting is crucial for applications in diagnostics and research.
• Existing methods can be complex, costly, or require particle labeling.

Purpose of the Study:

• To develop a facile, label-free method for sorting particles of different sizes.
• To utilize light-induced thermal buoyancy for particle manipulation in a microchamber.

Main Methods:

• Computational modeling was employed to design the particle sorting system.
• A microfluidic chamber inclined at an angle was used, containing gold nanoparticles and microparticles.
• Ultraviolet light illumination of gold nanoparticles generated thermal buoyancy, driving convective fluid flow.

Main Results:

• The convective flow, controlled by light intensity and gold nanoparticle concentration, separated particles based on size.
• Particle separation was achieved along the inclined wall of the microchamber.
• Increased inclination angle and particle size difference enhanced separation distance.

Conclusions:

• The developed system offers a low-cost, membrane-less, and label-free approach for particle sorting.
• This method is adaptable for various applications requiring precise particle separation.
• The technique leverages photothermal effects for efficient microparticle manipulation.