Acoustic Confinement Structure for Microfluidic Particle Focusing

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Solution Overview

Problem

Current microfluidic focusing techniques, such as standing wave acoustophoresis, face limitations in increasing the speed of particle focusing due to constraints on frequency and driving power, and often require sheath fluid flows orders of magnitude greater than the sample fluid, making them inefficient for effective particle or cell separation and enrichment.

Innovation Solution

A focusing arrangement featuring a channel with acoustic confinement structures and pillar arrays that confine acoustic fields and particle flows separately, allowing for the generation of standing waves and efficient focusing of particles away from channel walls, enabling improved focusing efficiency and scalability across multiple channels by controlling acoustic fields and resonance conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If frequency and driving power are increased to increase particle migration speed in standing wave acoustophoresis, then focusing speed is improved, but device complexity and energy consumption increase

Engineering Contradiction:
Improveparticle migration speedVSAvoidacoustic field control complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The device divides the channel into multiple segments with independent acoustic confinement structures, each capable of focusing particles locally. This segmentation allows complex focusing tasks to be distributed across multiple simpler units, reducing overall system complexity while maintaining high focusing speed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a spatial dimension by arranging acoustic confinement structures at different positions along the channel. Instead of relying solely on increasing frequency and power, the system uses spatial distribution of acoustic fields to achieve rapid particle migration through coordinated focusing at multiple locations

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

2Productivity

If sheath fluid flow is increased to achieve sufficient particle focusing, then focusing efficiency is improved, but fluid consumption and system complexity increase

Engineering Contradiction:
Improveparticle focusing efficiencyVSAvoidsheath fluid volume
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The invention replaces the mechanical hydrodynamic focusing system with an acoustic field-based system. Instead of using high-volume sheath fluid flows to mechanically focus particles, acoustic radiation forces are used to manipulate particle positions, dramatically reducing fluid consumption while maintaining or improving focusing efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the physical parameters used for focusing from hydrodynamic flow rates to acoustic field parameters (frequency, amplitude, confinement structure geometry). This parameter transformation enables efficient particle focusing with minimal fluid consumption by exploiting acoustic radiation forces rather than relying on high shear flows

Inventive Principle:
Principle #35Parameter changes

3Productivity

If acoustic fields are extended across multiple channels to increase throughput, then productivity is improved, but cross-channel interference increases

Engineering Contradiction:
Improvemulti-channel throughputVSAvoidcross-channel acoustic interference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Each channel is equipped with independent acoustic confinement structures that are spatially segmented from other channels. This segmentation creates isolated acoustic zones within each channel, preventing acoustic field interference between adjacent channels while enabling parallel processing and high throughput

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The acoustic confinement structures are designed to create localized acoustic fields with specific properties tailored to each channel's requirements. This local optimization ensures that acoustic energy is concentrated where needed within each channel, minimizing spill-over and interference with neighboring channels while maximizing focusing efficiency

Inventive Principle:
Principle #3Local quality

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 enhances particle focusing efficiency, allows for parallel channel focusing, and increases throughput by optimizing acoustic field distribution and resonance, reducing cross-channel interference and improving uniformity, thus overcoming the limitations of existing methods.

Implementation Method 1

In prior art standing wave acoustophoresis systems acoustic radiation forces are used to separate particles or cells from a liquid

Methodology Applied
Scientific EffectAcoustic radiation forces: Acoustic Radiation Pressure

Implementation Method 2

The focusing arrangement comprises an acoustic transducer which is adapted for generating a standing wave between the acoustic field boundaries of the at least one acoustic confinement structure

Methodology Applied
Scientific EffectStanding wave: Resonance

Implementation Method 3

In prior art standing wave acoustophoresis systems acoustic radiation forces are used to separate particles or cells from a liquid

Methodology Applied
Scientific EffectAcoustophoresis: Acoustic Radiation Pressure

Data Source

PatentEP3493907B1Method and arrangement for focusing objects in a flow
Publication Date: 2023.10.04 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3493907B1 patent drawingFigure 1~2
  • EP3493907B1 patent drawingFigure 3~4
  • EP3493907B1 patent drawingFigure 5~6

AI summary

A focusing arrangement (100) for focusing particles or cells in a flow. The arrangement comprising at least one channel (110) for guiding the flow, the channel comprising at least one particle confinement structure comprising particle flow boundaries (112) and at least one acoustic confinement structure (120) comprising acoustic field boundaries (122) adapted for confining acoustic fields, wherein the acoustic field boundaries (122) are different from the particle flow boundaries (112) and wherein the at least one acoustic confinement structure (120) is arranged with regard to the channel (110) to confine acoustic fields at least partially, in the channel (110).