Microfluidic Component for Electrical Impedance Measurement

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Solution Overview

Problem

Current microfluidic devices for measuring electrical impedance across biological objects, such as spheroids, face issues with suboptimal electrode configurations, non-transparent materials, and inability to visualize the biological object during measurement, which hinders accurate characterization and monitoring.

Innovation Solution

A microfluidic component with a layered structure featuring electrodes positioned to allow field lines to pass through the biological object, integrated with transparent materials for optical tracking and a hydrodynamic trap to maintain the object in a stable position, enabling reliable electrical impedance measurements and visualization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If coplanar electrodes are used in conventional microfluidic devices, then the device structure is simple and easy to manufacture, but the field lines do not optimally penetrate the biological objects and measurement precision is poor

Engineering Contradiction:
Improveelectrical impedance measurement accuracyVSAvoidelectrode configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from coplanar electrodes (2D arrangement) to oppositely arranged electrodes separated by the microfluidic channel (3D arrangement). This dimensional change allows field lines to pass through the biological objects perpendicular to the channel flow direction, significantly improving measurement precision while the layered structure keeps manufacturing feasible through standard PCB or lithography techniques.

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

2Measurement precision

If non-transparent materials are used for electrodes or chamber walls, then electrical impedance measurement is improved, but optical tracking and visualization of biological objects become impossible

Engineering Contradiction:
Improveelectrical impedance measurement capabilityVSAvoidoptical transparency for visualization
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent applies local quality by making only the necessary components (electrodes and channel walls) transparent rather than the entire device. The electrodes are made of transparent conductive materials like ITO or FTO, and the channel walls are made of transparent polymers or glass, allowing simultaneous electrical impedance measurement and optical visualization through the same region where biological objects are positioned.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If biological objects are placed in contact with electrodes or too far away, then device configuration is simplified, but measurement precision and field penetration are suboptimal

Engineering Contradiction:
Improvefield penetration through biological objectVSAvoidbiological object positioning
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent uses hydrodynamics to automatically position biological objects at the optimal measurement location. A hydrodynamic trap created by channel geometry (constriction or expansion) and flow rate control concentrates and holds spheroids or cells between the oppositely arranged electrodes, ensuring consistent positioning without manual intervention while maintaining optimal field penetration.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Adaptability or versatility

If conventional microfluidic devices are used, then manufacturing is straightforward, but the ability to simultaneously perform electrical impedance measurement and optical tracking is limited

Engineering Contradiction:
Improvemulti-modal measurement capabilityVSAvoidintegrated structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by designing a single microfluidic device that simultaneously performs electrical impedance measurement and optical tracking. The transparent electrodes and channel walls serve dual purposes: conducting electrical fields for impedance measurement and allowing light transmission for optical visualization, eliminating the need for separate measurement systems.

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

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

Facilitates accurate and reliable electrical impedance measurements while allowing for optical monitoring, enhancing the characterization of biological objects and enabling counting of objects in a fluid flow.

Implementation Method 1

measuring electrical impedance across a biological object

Methodology Applied
Scientific EffectElectrical impedance measurement: Electrical Resistance

Implementation Method 2

The microfluidic space includes a hydrodynamic trap forming said measurement zone

Methodology Applied
Scientific EffectHydrodynamic trap: Fluid Spray

Data Source

PatentEP4147780B1Microfluidic component used for a measurement of electrical impedance through a biological object
Publication Date: 2023.10.04 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4147780B1 patent drawingFigure 1~3
  • EP4147780B1 patent drawingFigure 4~5
  • EP4147780B1 patent drawingFigure 6~7

AI summary

The invention relates to a microfluidic component (1) used for measuring electrical impedance through a biological object, said component comprising: - A microfluidic space (10) including a measurement zone (2), - At least two electrodes (40, 41) arranged opposite each other, on either side of the measurement zone (2), - The component (1) being formed by the assembly of at least two superimposed layers along a longitudinal junction plane, called lower layer (3) and upper layer (5), - The two layers each having at least one cavity (30, 50), - The two layers being assembled one on top of the other so as to place the two cavities opposite each other to form said microfluidic space.