Acoustophoretic Polymer Chip Resonance Actuation

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Solution Overview

Problem

Polymer chips used in acoustophoresis have low acoustophoretic efficiency and throughput due to inadequate design principles borrowed from silicon and glass substrates, which do not account for the unique acoustic resonance characteristics of polymeric materials.

Innovation Solution

The method involves using a polymer substrate with at least two ultrasound transducers actuated at a frequency corresponding to an acoustic resonance peak of the entire substrate, including the microfluidic flow channel, to create efficient acoustic forces for particle manipulation, focusing, and separation, rather than relying on dimensions-based frequency selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polymer substrate is used instead of silicon or glass, then ease of manufacture and cost are improved, but acoustophoretic efficiency and throughput deteriorate

Engineering Contradiction:
Improveease of manufactureVSAvoidthroughput
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention changes the actuation frequency parameter from conventional channel-dimension-based selection to substrate-resonance-based selection. By identifying and actuating at the acoustic resonance frequency of the entire polymer substrate (typically 0.5-5 MHz), the system generates strong three-dimensional standing waves throughout the substrate volume, creating intense acoustic radiation forces that dramatically improve particle manipulation efficiency and throughput in polymer chips

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes mechanical vibration through ultrasound transducers that generate ultrasonic waves at the substrate's acoustic resonance frequency. This resonance-induced vibration creates strong standing waves within the polymer substrate, producing acoustic radiation forces that effectively manipulate particles despite the polymer material's inherent acoustic properties, thereby achieving high throughput

Inventive Principle:
Principle #18Mechanical vibration

2Ease of manufacture

If polymer substrate is used instead of silicon or glass, then ease of manufacture and cost are improved, but acoustophoretic efficiency deteriorates

Engineering Contradiction:
Improveease of manufactureVSAvoidacoustophoretic efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the actuation frequency parameter from conventional channel-dimension-based selection to substrate-resonance-based selection. By identifying and actuating at the acoustic resonance frequency of the entire polymer substrate (typically 0.5-5 MHz), the system generates strong three-dimensional standing waves throughout the substrate volume, creating intense acoustic radiation forces that dramatically improve particle manipulation efficiency and throughput in polymer chips

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from two-dimensional surface acoustic waves or channel-based acoustic fields to three-dimensional volume resonances throughout the substrate. By exciting the entire substrate volume at its resonant frequency, the system creates standing waves that penetrate and utilize the full three-dimensional space of the polymer substrate, generating strong acoustic radiation forces throughout the channel volume for reliable particle manipulation

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

3Device complexity

If conventional frequency selection based on channel dimensions is used, then device complexity is reduced, but acoustophoretic efficiency deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidthroughput
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The invention implements feedback by measuring the acoustic resonance frequency of the specific polymer substrate through impedance analysis or frequency sweeping, then using this measured value to set the optimal actuation frequency. This feedback loop ensures that each device operates at its precise resonant frequency, maximizing acoustic radiation forces and throughput while accommodating variations in substrate geometry and material properties

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention performs preliminary action by pre-characterizing the acoustic resonance frequency of the polymer substrate during manufacturing or initial setup. This pre-determined resonance frequency is then used to configure the ultrasound transducer operating parameters before actual particle manipulation begins, ensuring optimal performance without requiring complex real-time adjustments during operation

Inventive Principle:
Principle #10Preliminary action

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 significantly enhances acoustophoretic operations in polymer chips, achieving higher separation efficiency and throughput by leveraging three-dimensional volume resonances and asymmetric actuation of transducers, making polymeric substrates viable for acoustophoretic applications.

Implementation Method 1

a standing wave may appear in the channel. This standing wave exerts a force on the particles in the suspension dependent on the acoustic contrast of each individual particle

Methodology Applied
Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Implementation Method 2

Acoustophoresis has been used inter alia for separating different types of cells in suspensions

Methodology Applied
Scientific EffectAcoustophoresis:

Implementation Method 3

a standing wave may appear in the channel. This standing wave exerts a force on the particles

Methodology Applied
Scientific EffectStanding wave:

Implementation Method 4

actuating the at least two ultrasound transducers at a frequency f that corresponds to an acoustic resonance peak of the substrate including the microfluidic flow channel

Methodology Applied
Scientific EffectAcoustic resonance: Resonance

Data Source

PatentEP3676005B1Methods and devices for acoustophoretic operations in polymer chips
Publication Date: 2024.09.25 ACOUSORT
  • EP3676005B1 patent drawingFigure 1A~1B
  • EP3676005B1 patent drawingFigure 1C~1D
  • EP3676005B1 patent drawingFigure 1E~1I

AI summary

The invention relates to a method of performing an acoustophoretic operation, comprising the steps of: a. providing an acoustophoretic chip comprising a polymer substrate in which a microfluidic flow channel is positioned, b. providing at least one ultrasound transducer in acoustic contact with one surface of the substrate, c. actuating the at least one ultrasound transducer at a frequency f that corresponds to an acoustic resonance peak of the substrate including the microfluidic flow channel filled with a liquid suspension,and d. providing the liquid suspension in the flow channel to perform the acoustophoretic operation on the liquid suspension.The invention further relates to an acoustophoretic device, a method of producing an acoustophoretic device, and a microfluidic system comprising the acoustophoretic device.