Microfluidic Cavity Washing via Gas Bubble Displacement

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Solution Overview

Problem

Microfluidic cartridges require multiple time-consuming and labor-intensive washing steps to detect low concentrations of biological substances, with residual substances often remaining in chambers due to inefficient liquid removal, increasing the need for washing liquid and space.

Innovation Solution

A method where a gas bubble is introduced into the cavity before the washing liquid, displacing and removing the liquid to be washed out, reducing the need for subsequent washing liquid and potentially reducing washing time, using a gas bubble with a volume of approximately 40-60% of the cavity volume, which can be provided within the microfluidic component itself.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple washing steps are performed to remove residual substances from chambers, then detection sensitivity is improved, but measurement time increases and productivity decreases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by introducing a gas phase into the chamber before the washing liquid to pre-displace the reaction liquid. This preliminary gas introduction creates a head start for liquid removal, reducing the burden on subsequent washing steps and enabling faster achievement of desired residual concentration levels.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes pneumatic-hydraulic coupling by combining gas phase introduction with liquid phase washing. The gas bubble acts as a pneumatic precursor that facilitates the hydraulic washing process, creating an efficient two-phase cleaning mechanism that reduces overall washing time while maintaining detection sensitivity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Measurement precision

If multiple washing steps are performed to achieve desired residual concentrations, then purity of detection is improved, but loss of time increases

Engineering Contradiction:
Improvepurity of detectionVSAvoidwashing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The gas phase is introduced as a preliminary action before washing liquid to pre-remove a significant portion of the reaction liquid. This preliminary displacement action reduces the time required for subsequent washing steps to achieve the desired purity levels for detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent exploits phase transitions by utilizing the gas-liquid phase boundary to enhance liquid removal. The gas bubble rising through the chamber creates efficient liquid displacement at the phase interface, accelerating the washing process while ensuring adequate purification for detection purposes.

Inventive Principle:
Principle #36Phase transitions

3Ease of operation

If conventional washing with liquid only is used, then ease of operation is maintained, but washing efficiency decreases and residual substances remain in corner regions

Engineering Contradiction:
Improveoperational simplicityVSAvoidwashing efficiency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent combines pneumatic (gas) and hydraulic (liquid) phases to create a two-phase washing system. The gas bubble rises through the chamber creating efficient liquid displacement that reaches corner regions better than liquid alone, improving washing efficiency while maintaining operational simplicity through automated phase introduction.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The rising gas bubble creates dynamic fluid motion and mixing effects that enhance liquid removal from difficult-to-reach areas including corner regions. This natural convective motion driven by the gas-liquid interface improves washing efficiency without requiring complex mechanical agitation devices.

Inventive Principle:
Principle #18Mechanical vibration

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 reduces the volume of washing liquid required and may allow for a single washing step to achieve desired residual concentrations, minimizing space and material needs while enhancing washing efficiency.

Implementation Method 1

A method is proposed wherein a gas is introduced into the cavity before the washing liquid is added. The gas, in the form of a bubble with a defined volume, displaces a large portion of the liquid to be washed out of the cavity through an outlet opening

Methodology Applied
Scientific EffectGas bubble displacement: Bubble

Data Source

PatentEP2624954B1Method for washing a microfluid cavity
Publication Date: 2020.08.26 BOEHRINGER INGELHEIM MICROPARTS GMBH
  • EP2624954B1 patent drawingFigure 1~2
  • EP2624954B1 patent drawingFigure 3a~3b
  • EP2624954B1 patent drawingFigure 4a~4g

AI summary

Method for washing a cavity in a microfluidic component and a microfluidic component for carrying out the method. The invention relates to a method for washing at least one cavity (20') in a microfluidic component, wherein, in the cavity (20'), a first liquid (F1) is present and at least one second liquid (F2) is supplied to the cavity (20') for washing. According to the invention, an air bubble (L) is fed to the cavity (20') before supply of the washing liquid (F2). The air bubble (L) which virtually acts as a barrier layer between the first liquid (F1) and the following washing liquid (F2), makes possible a notable increase in washing efficiency. Overall, this method leads to a saving in washing liquid (F2) and washing time. In addition, a microfluidic component is proposed for carrying out the method.