Anticipating Cutoff Diameters in Deterministic Lateral Displacement (DLD) Microfluidic Devices for an Optimized...

Area of Science:

• Microfluidics
• Particle Separation
• Nanotechnology

Background:

• Deterministic lateral displacement (DLD) devices utilize microfluidic channels with slanted pillars to separate particles based on size.
• Existing models predict a single cutoff diameter for DLD geometries, limiting design optimization.
• Accurate prediction of particle behavior in DLD devices is crucial for efficient separation.

Purpose of the Study:

• To investigate the variation of cutoff diameter along the DLD channel.
• To identify the cause of cutoff diameter variation, specifically the wall effect.
• To develop and validate a predictive model for DLD devices that accounts for the wall effect and improves design.

Main Methods:

• Experimental investigation of particle trajectories in DLD devices.
• Numerical simulations to analyze fluid dynamics and particle behavior.
• Development of a new predictive model incorporating channel width and number of pillars.

Main Results:

• The cutoff diameter in DLD devices is not constant and varies along the channel, particularly in narrow pillar arrays.
• Boundary effects at channel walls, termed the wall effect, induce unexpected particle trajectories and reduce separation efficiency.
• The proposed predictive model, considering the number of pillars in the cross dimension, accurately anticipates the wall effect.

Conclusions:

• The wall effect significantly influences particle separation in DLD devices.
• A novel predictive model has been developed and experimentally validated to account for the wall effect.
• This model enables more robust design of DLD devices for enhanced particle separation efficiency.