Deterministic Lateral Displacement Pillar Arrays for Particle Separation
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Solution Overview
Problem
Microfluidic devices face challenges in efficiently separating particles due to the time reversibility of laminar flow, which complicates mixing of parallel flow streams and requires additional complexity with extra channels and pressure controls for hydrodynamic focusing.
Innovation Solution
A deterministic lateral displacement array is formed within a substrate, comprising a condenser and separator portion with arrays of pillars that concentrate and separate particles based on size by manipulating their flow paths, eliminating the need for extra channels or electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydrodynamic focusing with extra channels and pressure controls is used, then particle concentration and stream control are improved, but device complexity increases
Solution Approach 1:
The invention extracts and eliminates the need for extra channels and pressure control systems by using a single channel with deterministic lateral displacement pillars. The pillars themselves perform the focusing function that previously required separate hydrodynamic focusing channels, thereby reducing device complexity while maintaining separation resolution.
Solution Approach 2:
The pillar array structure performs multiple functions automatically: it focuses particles, separates them by size, and controls their positions without requiring external pressure controls or additional channels. The geometric arrangement of pillars self-regulates particle flow paths based on particle diameter, eliminating the need for complex external control systems.
2Use of energy by moving object
If laminar flow with time reversibility is used, then low energy consumption is achieved, but mixing of parallel flow streams becomes challenging
Solution Approach 1:
The invention introduces asymmetric pillar arrangements that create deterministic lateral displacements for different particle sizes. The asymmetric geometry causes larger particles to follow different paths than smaller particles, enabling effective separation and mixing control in laminar flow without requiring additional energy input or complex flow manipulation.
Solution Approach 2:
The invention adds a lateral displacement dimension to particle transport by using pillars arranged at specific angles and positions. This transforms the flow from simple parallel streams into multi-dimensional particle trajectories, enabling mixing and separation capabilities in laminar flow while maintaining low energy consumption.
3Measurement precision
If particle streams are concentrated to reduce diffusion effects, then separation precision is improved, but particle concentration increases leading to higher diffusion
Solution Approach 1:
The invention segments the particle stream into distinct pathways based on particle size using the pillar array. Larger particles are directed along one path while smaller particles follow another, effectively segmenting the concentrated stream to prevent diffusion-induced mixing and maintain separation precision despite high local concentrations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies particle separation by focusing particles into narrow jets without additional flow streams or pressure control, reducing diffusion effects and enabling high-resolution fractionation, increasing particle concentration, and allowing flexible positioning of particle streams within a single channel.
Implementation Method 1
In microfluidic devices, the fluid behaves according to the laws of laminar flow, which has high viscosity and no inertia motion.
Implementation Method 2
Adjacent flow streams can be used to compress and 'sculpt' a liquid stream without diluting the contents (e.g. particles, analytes) of the stream itself. This method is called hydrodynamic focusing and has been used to generate concentrated 'jets' of fluid flow
Data Source
AI summary
A deterministic lateral displacement array that includes a channel, within a substrate, having a first sidewall, a second sidewall, and a channel length. A condenser portion that includes an entry port and an exit port. A first array of pillars is disposed between the entry port and the exit port of the condenser portion along the channel length, the first array of pillars operative to drive a first material particle and a second material particle towards the first sidewall of the channel. A separator portion that includes an entry port and an exit port, and a second array of pillars disposed between the entry port and the exit port of the separator portion along the channel length, the pillars operative to drive the first material particle towards the second sidewall of the channel.