Conductive Membrane Valve for Microfluidic Fluid Control

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Solution Overview

Problem

Current microfluidic valve designs, including mechanical, membrane, bubble, and capillary valves, are costly and hinder performance due to bulky actuators and chemical interactions with reagents, leading to low fidelity and leakage issues in Lab-on-a-chip devices.

Innovation Solution

The development of electrically actuated, one-time openable conductive membrane valves that leverage existing electronics within microfluidic device readers, using a conductive membrane sandwiched between microfluidic channels with thinned regions that melt upon electric current application to control fluid flow, eliminating the need for bulky actuators and preventing reagent leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical actuators are used to activate valves, then valve function is achieved, but device complexity and cost increase due to bulky components

Engineering Contradiction:

Improvevalve functionVSAvoidactuator size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical actuators with an electrical field-based system. A conductive trace embedded in the substrate allows electrical current to flow, generating heat that locally melts the membrane material to open the valve. This eliminates bulky mechanical components while achieving reliable valve actuation through purely electrical means.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of the membrane material from solid to liquid through localized heating. The conductive trace delivers electrical current that generates heat sufficient to melt the membrane at specific locations, causing it to lose structural integrity and open the valve. This phase transition mechanism enables reliable valve opening without mechanical movement.

Inventive Principle:

Principle #36Phase transitions

2Reliability

If conventional membrane valves are used, then fluid control is achieved, but reagent leakage occurs due to chemical interactions

Engineering Contradiction:

Improvefluid controlVSAvoidchemical interactions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces chemical interaction-based valve mechanisms with a physical field-based approach. Instead of relying on chemical properties of the membrane material for valve function, the system uses electrical current to generate heat that physically melts the membrane. This substitution eliminates chemical interactions between the valve material and reagents, preventing leakage while maintaining fluid control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple valves are integrated into microfluidic devices, then functionality is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvedevice functionalityVSAvoidfabrication complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges the valve actuation mechanism directly into the microfluidic device substrate by embedding conductive traces within the same fabrication process. This integration allows multiple valves to be manufactured simultaneously using standard microfluidic fabrication techniques, eliminating the need for separate actuator components and simplifying assembly. The unified manufacturing approach maintains device functionality while reducing fabrication complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 solution enables high-fidelity, scalable, and cost-effective fluid control within microfluidic devices, allowing for large numbers of valves to be integrated without reagent leakage, improving the performance and reducing the physical footprint of microfluidic systems.

Implementation Method 1

A conductive trace to open the membrane valve by supplying an electric current to heat and melt a thinned region of the membrane valve

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

thinned regions that melt upon electric current application to control fluid flow

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11478793B2Microfluidic devices

Publication Date: 2022.10.25 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

In an example implementation, a microfluidic device includes a first layer with a first microfluidic channel and a second layer with a second microfluidic channel. The first and second channels are adjacent to one another at a channel intersection, and a conductive membrane valve extends across and covers the channel intersection to separate the first and second channels. The microfluidic device includes a conductive trace to open the membrane valve and join the first and second channels by supplying an electric current to heat and melt a thinned region of the membrane valve.