Analyte Detection Microsystem Using Dielectrophoretic Drop Formation

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Solution Overview

Problem

Existing methods for detecting analytes in liquids face challenges such as reduced analyte concentration due to hydrodynamic forces in microchannels, contamination risks from channel walls, and vibration damping, which degrade sensor sensitivity and quality factor.

Innovation Solution

The method involves forming a finger of liquid on a surface using liquid dielectrophoresis, which breaks into drops that come into contact with a detection surface, reducing the influence of viscous forces and contamination risks, and allowing the sensor to operate without liquid in the vibration zone, thus preserving the quality factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If liquid circulates through a microchannel to deliver analytes to the sensor, then analyte delivery is achieved, but hydrodynamic forces reduce analyte concentration at the sensor surface

Engineering Contradiction:
Improveanalyte concentrationVSAvoidhydrodynamic forces
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The invention extracts the harmful hydrodynamic forces by removing the liquid flow from the detection zone. Instead of circulating liquid through a microchannel past the sensor, the sensor surface is brought into direct contact with the liquid sample, allowing analytes to reach the sensor without being subjected to viscous drag and hydrodynamic forces that would otherwise reduce their concentration at the sensor surface.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces a hydrophobic barrier layer as an intermediary between the liquid sample and the sensor surface. This layer allows the liquid to contact the sensor while preventing the formation of a continuous liquid flow path, thereby eliminating hydrodynamic forces while maintaining analyte delivery through direct contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If liquid flows through a microchannel with micrometric dimensions, then liquid transport is achieved, but viscosity forces hold back analytes near the walls

Engineering Contradiction:
Improveanalyte delivery efficiencyVSAvoidviscous damping
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The invention extracts the harmful viscous damping by eliminating the microchannel flow geometry. By placing the sensor surface directly into contact with the liquid sample without confining it to narrow channels, the invention removes the source of viscous forces that would otherwise hold back analytes near the walls and reduce delivery efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the sensor is immersed in liquid for detection, then analyte access is improved, but vibration damping degrades the quality factor

Engineering Contradiction:
Improvedetection sensitivityVSAvoidquality factor
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention applies local quality by creating a selective contact arrangement where only the detection surface of the sensor is in contact with the liquid sample, while the vibration zone remains protected. The hydrophobic barrier layer enables this localized contact, allowing analyte access to the detection surface while preventing liquid from entering the vibration zone and causing damping.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The hydrophobic barrier layer serves as an intermediary that permits selective interaction: it allows analytes to reach the detection surface for sensitive measurement while simultaneously preventing liquid from contacting the vibration zone, thereby preserving the quality factor and reliability of the sensor.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If liquid circulates in a microchannel, then sample analysis is enabled, but contamination from channel walls occurs

Engineering Contradiction:
Improvedetection capabilityVSAvoidcontamination
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the source of contamination by removing the microchannel walls from the system. By placing the sensor surface directly into contact with the liquid sample without using confining channels, the invention eliminates the wall materials that would otherwise leach contaminants into the sample and interfere with analyte detection.

Inventive Principle:
Principle #2Taking out (Extraction)

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 the concentration of analytes reaching the detection surface, reduces contamination risks, and maintains the sensor's quality factor, enabling precise and rapid detection of multiple analyte categories.

Implementation Method 1

forming finger of liquid on said first surface by liquid dielectrophoresis, under the effect of an electrical control

Methodology Applied
Scientific EffectLiquid dielectrophoresis: Dielectric

Implementation Method 2

stopping the electrical control, so that the finger of liquid breaks by capillarity, generating at least one drop

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

the mass of the analytes of interest which are deposited on the detection surface of the oscillator is directly correlated with this frequency divergence

Methodology Applied
Scientific EffectGravimetry:

Implementation Method 4

forming finger of liquid on said first surface by liquid dielectrophoresis, under the effect of an electrical control

Methodology Applied
Scientific EffectElectrical field: Electric Field

Data Source

PatentEP2673093B1Method and microsystem for detecting analytes which are present in drops of liquid.
Publication Date: 2022.09.07 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2673093B1 patent drawingFigure 1~2A
  • EP2673093B1 patent drawingFigure 2B~3
  • EP2673093B1 patent drawingFigure 4A~4B

AI summary

The invention concerns a method of detecting analytes of interest which are present in a liquid. The method includes the steps of forming drops of liquid on a first surface (24) by capillary breaking of a finger of liquid, which is initially formed by liquid dielectrophoresis. The thus formed drops each come into contact with a different detection surface (31), which is arranged facing the first surface (24). Analytes of interest which are present in each of the drops are detected at the corresponding detection surface.