Microfluidic Analysis Chamber Isolation for Bubble-Free Sampling

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Solution Overview

Problem

The presence of bubbles in microfluidic networks, generated by pneumatic activation of membranes and high temperatures, disrupts analysis and leads to erroneous results in microfluidic devices.

Innovation Solution

A process that isolates the analysis chamber by maintaining input and output valves closed, opens an intermediate valve to allow liquid sample analysis, and uses a protective chamber to trap bubbles generated by pneumatic actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pneumatic actuation is used to control microfluidic valves, then valve control reliability is improved, but bubble generation increases due to membrane porosity

Engineering Contradiction:
Improvevalve control reliabilityVSAvoidbubble generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The microfluidic network is segmented into distinct functional zones: a reaction zone containing the analysis chamber isolated from bubble generation, and a bubble management zone including protection chambers and bubble traps. This spatial segmentation allows pneumatic valves to be actuated reliably while confining bubbles to specific regions away from the analysis chamber.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Protection chambers and bubble traps are introduced as intermediary elements between the pneumatic valve system and the analysis chamber. These intermediaries capture and contain bubbles generated by pneumatic actuation, preventing them from entering the analysis chamber while allowing the pneumatic system to continue functioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high temperature incubation is applied to promote biological reactions, then reaction efficiency is improved, but bubble formation increases

Engineering Contradiction:
Improvereaction efficiencyVSAvoidbubble formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system converts the harmful effect of temperature-induced bubble formation into a beneficial outcome by directing bubbles toward protection chambers and bubble traps. The same thermal energy that causes bubble formation is harnessed to drive biological reactions, while the resulting bubbles are systematically captured and isolated from the analysis chamber.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If deformable membranes are made porous to air for pneumatic control, then valve actuation is improved, but bubble propagation through the network increases

Engineering Contradiction:
Improvevalve actuationVSAvoidbubble propagation
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

Bubbles are extracted and removed from the main fluid pathway by introducing dedicated bubble management components such as protection chambers and bubble traps. These components selectively capture bubbles that propagate through the porous membranes, separating the bubble management function from the main fluid flow and analysis functions.

Inventive Principle:
Principle #2Taking out (Extraction)

4Duration of action of stationary object

If long duration pneumatic pressure is applied to maintain valve state, then valve stability is improved, but bubble injection into the network increases

Engineering Contradiction:
Improvevalve stabilityVSAvoidbubble injection
Core Design Contradiction:
Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Protection chambers and bubble traps are pre-positioned in the fluid pathway upstream of the analysis chamber. Before bubbles can be injected into the analysis chamber by prolonged pneumatic actuation, they are captured by these pre-positioned protective elements, allowing valves to maintain stable states for extended durations without compromising analysis chamber integrity.

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 process effectively prevents bubbles from entering the analysis chamber, ensuring accurate and reliable analysis by maintaining a bubble-free environment during liquid sample analysis.

Implementation Method 1

Each microfluidic valve being pneumatically actuated and comprising a cavity and a deformable membrane inside the cavity, so as to confer two distinct states to the valve, an open state in which it allows a liquid to pass and a closed state in which it blocks the passage of the liquid

Methodology Applied
Scientific EffectPneumatic actuation: Pressure Increase

Implementation Method 2

A deformable membrane is controlled to deform in said chamber in order to confer two distinct states to the capsule, a first state in which the inlet channel and the outlet channel communicate with each other through the chamber so as to allow a transfer of fluid

Methodology Applied
Scientific EffectMembrane deformation: Deformation

Implementation Method 3

using the protective microfluidic chamber to trap the bubbles generated by the pneumatic actuation of at least one microfluidic valve of the microfluidic device

Methodology Applied
Scientific EffectBubble trapping: Physical Containment

Implementation Method 4

Similarly, it is known that high temperatures (60°C-90°C) can promote the formation of bubbles in a microfluidic network

Methodology Applied
Scientific EffectThermal bubble formation: Heating

Data Source

PatentEP4529982A1Method for analyzing a liquid sample in a microfluidic device
Publication Date: 2025.04.02 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4529982A1 patent drawingFigure 1
  • EP4529982A1 patent drawingFigure 2A~2B
  • EP4529982A1 patent drawingFigure 3A~3B

AI summary

The invention relates to a method for analyzing a liquid sample, implemented in a microfluidic device comprising several microfluidic elements connected in series by microfluidic channels, from upstream to downstream, between a microfluidic inlet (1) and a microfluidic outlet (2) opening to the outside. Said method consists of: - Isolating a microfluidic analysis chamber (C2) by maintaining a microfluidic inlet valve (V1) and a microfluidic outlet valve (V4) in the closed state during an analysis of the liquid sample in said microfluidic analysis chamber (C2), - Using a protective microfluidic chamber (C3) to trap the bubbles generated by the pneumatic actuation of at least one microfluidic valve of the microfluidic device.