Phononic SAW Fluidics for Cell Lysis and Mixing

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Solution Overview

Problem

Microfluidics devices face challenges in efficiently manipulating biological samples, particularly in cell lysis and mixing at microfluidic dimensions due to laminar flow and turbulence issues, which complicates sample preparation and analysis.

Innovation Solution

A fluidics apparatus utilizing surface acoustic waves (SAWs) with a manipulation surface featuring periodic SAW scattering elements, such as phononic crystals, to refract and concentrate SAWs within the fluid sample, facilitating cell lysis and mixing by creating acoustic pressure fields and streaming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If surface acoustic waves are used to manipulate fluid samples, then cell lysis efficiency and mixing effectiveness are improved, but device complexity increases due to the need for piezoelectric substrates and interdigitated electrode transducers

Engineering Contradiction:
Improvecell lysis efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The piezoelectric substrate with interdigitated electrode transducers serves multiple functions: generating surface acoustic waves for cell lysis, creating acoustic streaming for mixing, and enabling temperature control through acoustic heating. This multi-functionality resolves the contradiction by achieving high productivity through a single integrated device architecture rather than requiring separate systems for each function.

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

Solution Approach 2:

The device utilizes changes in acoustic wave parameters (frequency, amplitude, wavelength) to achieve different manipulation effects. By adjusting these parameters, the same device structure can optimize for either cell lysis or mixing without requiring physical modification, thereby maintaining simplicity while achieving high efficiency in different operational modes.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If phononic crystals are introduced to refract and concentrate surface acoustic waves, then sample manipulation precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesample manipulation precisionVSAvoidease of manufacture
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The phononic crystal structure is segmented into periodic unit cells with specific geometric patterns. This segmentation allows the complex wave manipulation function to be achieved through repetition of simple, manufacturable units rather than requiring complex monolithic structures, thereby improving precision while maintaining ease of manufacture through modular fabrication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phononic crystal layer can be implemented as a disposable or easily replaceable component on the piezoelectric substrate. This approach allows optimization of manipulation precision in the phononic structure without permanently increasing the complexity of the core piezoelectric device, as the phononic layer can be manufactured separately and attached or replaced as needed.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If surface acoustic waves are used instead of thermal pumps for fluid handling, then mixing effectiveness is improved, but energy consumption increases

Engineering Contradiction:
Improvemixing effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The surface acoustic waves operate in periodic cycles, creating oscillatory flow patterns that enhance mixing through repeated deformation and reconfiguration of fluid elements. This periodic action achieves superior mixing effectiveness compared to continuous thermal pumping, while the energy is delivered in pulses rather than continuously, optimizing the energy-to-mixing-ratio despite higher peak power requirements.

Inventive Principle:
Principle #19Periodic 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

The apparatus achieves efficient cell lysis with high efficiency (>95%) and effective mixing, enabling reproducible sample preparation and analysis without the need for external actuation or lytic agents, suitable for point-of-care diagnostics and microfluidic applications.

Implementation Method 1

Surface acoustic waves can be conveniently formed at the surface of a piezoelectric material by the application of a suitable electrical signal to an electrode arrangement at the surface of the piezoelectric material

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

At the output transducer, the SAWs are converted back into an electrical signal

Methodology Applied
Scientific EffectConverse piezoelectric effect: Converse Piezoelectric Effect

Implementation Method 3

A manipulation surface with periodic SAW scattering elements, such as phononic crystals, to refract and concentrate SAWs within the fluid sample

Methodology Applied
Scientific EffectPhononic crystal scattering: Phononic Crystal

Implementation Method 4

facilitating cell lysis and mixing by creating acoustic pressure fields and streaming

Methodology Applied
Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Data Source

PatentEP2678107B1Fluidics apparatus for surface acoustic wave manipulation of fluid samples, use of fluidics apparatus and process for the manufacture of fluidics apparatus
Publication Date: 2020.01.08 THE UNIV COURT OF THE UNIV OF GLASGOW
  • EP2678107B1 patent drawingFigure 1~3
  • EP2678107B1 patent drawingFigure 4~5
  • EP2678107B1 patent drawingFigure 6

AI summary

A fluidics apparatus for manipulation of at least one fluid sample is disclosed. A manipulation surface locates the fluid sample. A surface acoustic wave (SAW) generation material layer is provided. This is a polycrystalline material, textured polycrystalline material, biaxially textured polycrystalline material, microcrystalline material, nanocrystalline material, amorphous material or composite material. A transducer electrode structure arranged at the SAW generation material layer provides SAWs at the manipulation surface for interaction with the fluid sample. The manipulation surface has a phononic structure, for affecting the transmission, distribution and/or behaviour of SAWs at the manipulation surface. The apparatus is typically manufactured by reel-to-reel processes, to reduce the unit cost to a level at which the apparatus can be considered to be disposable after a single use.