Cross-Shaped Dilution Stage for Microfluidic Resistance Networks

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Solution Overview

Problem

Current microfluidic devices face challenges in achieving accurate dilution ratios for Point of Care (POC) Full Blood Count (FBC) tests due to the risk of bubble trapping at low flow rates, which prolongs device initialization and reduces efficiency.

Innovation Solution

A cross-shaped dilution stage design where the whole fluid volume is presented to an X-shaped dilution stage, allowing the whole diluent stream and a fraction of the sample stream to enter one outlet channel, and the remainder enters another, with fluid separation defined by an imaginary axis, reducing the need for low-flow channels and minimizing bubble trapping risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If low flow rates are used to achieve accurate dilution ratios, then measurement precision is improved, but device initialization time increases and reliability decreases due to bubble trapping

Engineering Contradiction:

Improvedilution ratio accuracyVSAvoiddevice initialization

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Instead of using low flow rates to achieve accurate dilution ratios, the patent inverts the approach by using high flow rates with a cross-shaped dilution stage design. The cross-shaped geometry naturally distributes fluid at high flow rates while maintaining accurate dilution ratios, eliminating bubble trapping issues associated with low flow rates.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from a traditional linear dilution channel to a cross-shaped (two-dimensional) dilution stage. This dimensional change allows simultaneous fluid distribution across multiple outlets while maintaining high flow rates, achieving both accurate dilution ratios and rapid initialization without bubble trapping.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If low flow rates are used to achieve accurate dilution ratios, then measurement precision is improved, but productivity decreases due to prolonged initialization

Engineering Contradiction:

Improvedilution ratio accuracyVSAvoiddevice initialization speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent inverts the conventional approach by demonstrating that high flow rates can achieve accurate dilution ratios through the cross-shaped dilution stage design, thereby eliminating the trade-off between precision and speed.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The cross-shaped dilution stage enables continuous high flow rate operation without interruption for bubble removal or initialization delays. The design maintains steady-state flow conditions immediately upon activation, ensuring both high productivity and measurement precision from the start.

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If complex channel geometries are used to control low flow rates, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvedilution ratio accuracyVSAvoidchannel geometry

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using complex geometries to control low flow rates, the patent inverts the approach by using a simple cross-shaped geometry to enable high flow rate operation while maintaining precise dilution control through natural fluid distribution.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent simplifies device complexity by transitioning to a cross-shaped (two-dimensional) dilution stage, which achieves accurate dilution ratios through its geometric configuration rather than complex channel routing, reducing manufacturing difficulty and device complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design simplifies fluid dilution, reduces start-up times, and lowers the risk of device failure by maintaining high flow rates and accurate dilution ratios, ensuring efficient sample preparation for FBC analysis.

Implementation Method 1

a first microfluidic channel in fluidic communication with a first inlet; and a second microfluidic channel in fluidic communication with a second inlet; wherein the micro fluidic resistance network further comprises a cross-shaped dilution stage

Methodology Applied

Scientific EffectFluid flow resistance: Pressure Drop

Data Source

PatentUS9180452B2Microfluidic resistance network and microfluidic device

Publication Date: 2015.11.10 KONINKLIJKE PHILIPS NV

AI summary

A microfluidic resistance network (20) is disclosed that comprises a first microfluidic channel (112) in fluidic communication with a first fluid inlet (22); and a second microfluidic channel (114) in fluidic communication with a second fluid inlet (24); wherein the microfluidic resistance network (20) further comprises a cross-shaped dilution stage (100) having the first microfluidic channel (112) as a first dilution stage inlet and the second microfluidic channel (114) as a second dilution stage inlet, the dilution stage further comprising a first microfluidic outlet channel (122) for combining a portion of a first fluid from the first microfluidic channel with a second fluid from the second microfluidic channel (114) and a second microfluidic outlet channel (124) for receiving the remainder of first fluid. A microfluidic device (200) comprising such a microfluidic resistance network (20) is also disclosed.