Microfluidic Particle Separation via Deterministic Lateral Displacement

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Solution Overview

Problem

Existing methods for separating particles by size, such as in blood samples, often require complex devices, multiple stages, and stochastic processes, leading to low throughput, incomplete fractionation, and high costs, especially when dealing with large biomolecules or particles with a wide size range.

Innovation Solution

A continuous flow microfluidic device with a series of separation areas and non-clogging pathways, where particles are separated based on deterministic lateral displacement through an array of micro-posts, allowing particles above a critical size to be moved in different directions than smaller particles, preventing clogging and enabling efficient separation of particles from 1 µm to 20 µm in a single device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional separation methods (gel electrophoresis, field-flow fractionation, sedimentation, size exclusion chromatography) are used, then particles can be separated by size, but the separation process is slow, has low throughput, and requires complex multi-stage devices

Engineering Contradiction:
Improveseparation throughputVSAvoidseparation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The device divides the separation process into multiple parallel separation areas, each handling a specific size range. This segmentation allows simultaneous processing of different particle sizes, dramatically increasing throughput compared to sequential conventional methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from one-dimensional separation (single channel) to two-dimensional separation (multiple parallel channels with different critical sizes). This dimensional expansion enables concurrent separation of multiple particle size ranges, achieving high throughput without increasing separation time.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If particles with a wide size range (1 µm to 20 µm) are separated using conventional methods, then complete fractionation is achieved, but multiple devices or stages are required, increasing device complexity

Engineering Contradiction:
Improvesize range coverageVSAvoidnumber of separation stages
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each separation area is designed with adjustable parameters (channel dimensions, post array geometry) that can be optimized for different particle size ranges. This universal design allows a single device to handle the complete size range from 1 µm to 20 µm by activating appropriate separation areas, eliminating the need for multiple specialized devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The device employs a hierarchical structure where separation areas with different critical sizes are nested within a single integrated chip. Smaller critical size separations are contained within larger critical size separations, allowing cascading fractionation of particles across the entire size range in one pass through the device.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Productivity

If high flow rates are used to increase throughput, then separation speed improves, but flow becomes turbulent and diffusion-induced mixing increases, reducing resolution

Engineering Contradiction:
Improveflow rateVSAvoidseparation resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The device maintains laminar flow at high throughput by dynamically adjusting critical parameters: channel height and width are optimized to maintain appropriate Reynolds numbers, and post array geometry is scaled to match flow conditions. This parameter optimization allows high flow rates without transitioning to turbulent flow, preserving separation resolution.

Inventive Principle:
Principle #35Parameter changes

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

The device achieves efficient separation of particles across a wide size range without clogging, allowing for high flow rates and low Reynolds numbers, maintaining laminar flow and reducing diffusion-induced mixing, thereby improving resolution and throughput while simplifying fluid handling.

Implementation Method 1

particles are separated based on deterministic lateral displacement through an array of micro-posts, allowing particles above a critical size to be moved in different directions than smaller particles

Methodology Applied
Scientific EffectDeterministic lateral displacement:

Implementation Method 2

allowing for high flow rates and low Reynolds numbers, maintaining laminar flow and reducing diffusion-induced mixing

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 3

reducing diffusion-induced mixing

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2040843B1Apparatus for continuous particle separation
Publication Date: 2020.02.26 THE TRUSTEES OF PRINCETON UNIV
  • EP2040843B1 patent drawingFigure 1
  • EP2040843B1 patent drawingFigure 2A~2B
  • EP2040843B1 patent drawingFigure 3

AI summary

The invention is directed to an apparatus and a method of separating particles, such as cells, from a heterogeneous fluid, such as blood, where the particles have a large range of sizes.