Microfluidic Sacrificial Valve Dissolution Actuation

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Solution Overview

Problem

Existing microfluidic devices require complex external triggers and multiple equipment/processes for actuating sacrificial valves, which complicates the manufacturing and operation of fluid control in microfluidic devices.

Innovation Solution

A microfluidic device with a sacrificial valve that dissolves upon contact with a fluid, eliminating the need for peripheral actuation mechanisms, using a gas pocket to prevent initial contact and a drive mechanism to induce fluid flow, thereby controlling the valve's actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sacrificial valves (wax or polymer films) are used, then liquid/vapour barrier function is achieved, but complex external actuation mechanisms (heaters, lasers, dispensers) are required

Engineering Contradiction:

Improveliquid/vapour barrier functionVSAvoidactuation mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sacrificial material itself performs the dual function of providing the liquid/vapour barrier and enabling its own removal through dissolution in the liquid sample, eliminating the need for separate actuation mechanisms. The material is selected to be inherently soluble in the sample matrix, allowing automatic valve opening upon sample introduction.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The complex external actuation mechanisms (heaters, lasers, dispensers) are completely removed from the system. Only the essential sacrificial material remains, which is strategically placed to block the flow path and automatically dissolves when exposed to the liquid sample, achieving valve actuation without any peripheral equipment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If sacrificial material is embedded in microchannel, then valve function is achieved, but multiple manufacturing processes (dispenser, heating) are required

Engineering Contradiction:

Improvevalve functionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The valve actuation function and sample introduction function are merged into a single process. The liquid sample that must be introduced into the device also serves as the solvent to dissolve and open the valve, eliminating the need for separate actuation steps and reducing manufacturing complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sacrificial material is designed as a consumable component that is inexpensive and easily replaceable. It is embedded directly in the microchannel using simple techniques and automatically dissolves after serving its valve function, requiring no complex manufacturing or actuation infrastructure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If gas pocket is provided between liquid and sacrificial member, then liquid contact is prevented, but valve actuation requires pressure differential to dissipate gas pocket

Engineering Contradiction:

Improvevalve sealingVSAvoidvalve actuation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

A gas pocket is intentionally introduced between the liquid sample and the sacrificial material to prevent premature contact and unintended valve opening. This preliminary protective measure ensures the valve remains sealed during device priming and sample loading, and only opens when sufficient pressure differential is applied to dissipate the gas pocket.

Inventive Principle:

Principle #9Preliminary anti-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

The solution allows for efficient, integrated fluid control with programmable flow and vapor barriers, simplifying manufacturing and operation, and enabling applications like mixing, blood separation, and on-board reagent storage without separate actuation.

Implementation Method 1

a gas pocket provided between the liquid and the sacrificial member of the valve... the gas pocket prevents liquid contact with the sacrificial member

Methodology Applied

Scientific EffectGas pocket barrier:

Implementation Method 2

the sacrificial member dissolves and the fluid may then pass from the first to the second region

Methodology Applied

Scientific EffectDissolution:

Implementation Method 3

a drive mechanism configured to induce flow in the liquid which operably drives the liquid towards the valve

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 4

By increasing the induced pressure differential across the liquid from upstream or applying a suction pressure, the gas pocket will dissipate and the liquid will make contact with the valve

Methodology Applied

Scientific EffectPressure-driven gas displacement: Pressure Gradient

Data Source

PatentUS9295990B2Microfluidic valve

Publication Date: 2016.03.29 DUBLIN CITY UNIVERSITY

AI summary

Microfluidic devices and in particular microfluidic devices incorporating a valve for selectively controlling the flow of a fluid within the microfluidic device are described. Specific examples of a microfluidic device are described, comprising a sacrificial valve, desirably one that is dissolvable on contact with a fluid or that is configured to disintegrate or dissolve on experiencing a predetermined pressure.