Multi-layer Microfluidic Test Card with Integrated Filter for WBC Analysis

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Solution Overview

Problem

Existing microfluidic systems for counting and differentiating white blood cells, such as those using slides or cuvettes, lack an efficient mechanism for quick and accurate analysis, especially with varying sample sizes.

Innovation Solution

A multiple layer test card with an input channel, a filter, and an output channel, where the filter is positioned between the input and output channels to collect and concentrate particles, allowing for optical visibility and staining of white blood cells, facilitating their detection and differentiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional slides or cuvettes are used for white blood cell analysis, then the device structure is simple, but the counting and differentiation efficiency is low

Engineering Contradiction:
Improvecounting and differentiation efficiencyVSAvoiddevice structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The device is segmented into multiple functional layers including input channel layer, filter layer, and output channel layer. Each layer performs a specific function: the input channel delivers fluid, the filter concentrates particles, and the output channel removes excess fluid. This segmentation enables efficient white blood cell analysis while maintaining manageable structural complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from traditional two-dimensional slides to a three-dimensional multi-layer structure. The vertical stacking of input channel, filter, and output channel layers creates additional spatial dimensions for fluid flow and particle concentration, significantly improving counting and differentiation efficiency within a compact footprint

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a filter is introduced to concentrate particles, then the particle concentration and optical visibility improve, but the device structure becomes more complex

Engineering Contradiction:
Improveparticle detection accuracyVSAvoidfilter integration structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The filter is merged with the microfluidic channel structure to form an integrated multi-layer device. The input channel, filter membrane, and output channel are combined into a single cohesive structure where fluid flows sequentially through each component. This merging achieves effective particle concentration for accurate detection while avoiding the complexity of separate, loosely-connected components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter membrane serves as an intermediary component between the input and output channels. It mediates the separation of particles from excess fluid, allowing concentrated white blood cells to accumulate on one side for optimal optical detection while maintaining structural integration with the microfluidic system

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the input and output channels are positioned close together, then the device size is reduced, but the particle collection efficiency decreases

Engineering Contradiction:
Improvedevice sizeVSAvoidparticle collection efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The device utilizes local quality differences created by the filter membrane to achieve effective particle separation in a compact space. The filter creates a localized region of high particle concentration on its surface, while the overall device maintains a small footprint through vertical layering. This allows efficient particle collection without requiring large horizontal distances between input and output channels

Inventive Principle:
Principle #3Local quality

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 system enables flexible analysis of white blood cells by concentrating and staining particles on a filter, allowing for efficient detection and differentiation, even with varying sample sizes, and is more adaptable than traditional cuvettes or slides for automated imaging.

Implementation Method 1

a filter coupled between the input channel and the output channel to receive fluid from the input channel and collect particles such that the collected particles are optically visible proximate a first surface of the filter

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2796871B1Particle imaging utilizing a filter
Publication Date: 2016.02.03 HONEYWELL INTERNATIONAL INC
  • EP2796871B1 patent drawingFigure 1~2
  • EP2796871B1 patent drawingFigure 3~4
  • EP2796871B1 patent drawingFigure 5

AI summary

A multiple layer test card (100, 500) including an input channel (110) formed in a layer of the test card, an output channel (120) formed in another layer of the test card, and a filter (115, 505, 605) coupled between the input channel and the output channel to receive fluid from the input channel and collect white blood cells such that the collected white blood cells are optically visible proximate a first surface (225) of the filter.