Stacked Microfluidic Dialysis Device with Compression-Sealed Membranes

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Solution Overview

Problem

Conventional microfluidic devices face challenges in efficiently dialyzing blood at lower flow rates for extended periods outside a clinical setting, with limitations in mass transfer rates due to thick boundary layers and risks of cross-contamination, and require complex and costly manufacturing processes.

Innovation Solution

The development of a microfluidic device with a configuration that includes semi-permeable membranes and a stackable, compression-sealed design with orthogonal vias and flow fields, reducing boundary layer thickness and cross-contamination risks, and allowing for efficient mass transfer and heat exchange using laminae with microchannels or flow fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional microfluidic devices are used for dialysis, then mass transfer occurs through membranes, but thick boundary layers reduce mass transfer efficiency

Engineering Contradiction:
Improvemass transfer efficiencyVSAvoiddialysis effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device divides the fluid flow path into multiple discrete microchannels separated by spacers, creating segmented flow patterns that enhance mixing and reduce boundary layer thickness compared to conventional single-channel designs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from planar 2D microchannels to three-dimensional stacked layers with vertical flow paths, adding a third dimension to mass transfer and significantly reducing diffusion distances across the membrane

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

2Reliability

If dialysis is performed outside a clinical setting at lower flow rates, then patient safety is improved by reducing blood outside the body, but dialysis effectiveness decreases

Engineering Contradiction:
Improvepatient safetyVSAvoiddialysis effectiveness
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Multiple stacked layers with numerous microchannels provide extensive membrane surface area in a compact device, enabling adequate dialysis treatment even at reduced flow rates suitable for home use

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The three-dimensional stacked architecture increases the membrane surface area available for mass transfer without proportionally increasing device volume, maintaining dialysis effectiveness at lower flow rates

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

3Ease of manufacture

If microfluidic devices are manufactured using conventional processes, then production cost is reduced, but manufacturing precision may be insufficient

Engineering Contradiction:
Improveproduction costVSAvoidmicrochannel dimensional accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The device is divided into separate laminated layers that can be manufactured independently using conventional techniques, then assembled together, allowing each layer to be produced with standard tolerances while achieving precise final microchannel dimensions through the stacking process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By moving critical precision requirements to the vertical stacking dimension rather than requiring high-precision lateral microchannel fabrication, the invention enables manufacturing with conventional techniques while maintaining functional precision

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

4Productivity

If multiple membranes are stacked to increase treatment capacity, then dialysis effectiveness is improved, but cross-contamination risk increases

Engineering Contradiction:
Improvetreatment capacityVSAvoidcross-contamination risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

Fluidic isolation elements and spacers physically segment and isolate adjacent microchannels and membrane surfaces, preventing cross-contamination between multiple treatment channels while maintaining high treatment capacity through parallel processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Spacer elements and sealing structures act as intermediary components between adjacent membranes and fluid channels, providing physical barriers that prevent direct contact and cross-contamination while allowing the stacked structure to function

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enhances mass transfer efficiency, reduces cross-contamination, and enables the use of conventional manufacturing techniques, making it feasible for low-cost, high-volume production of devices capable of dialyzing blood at lower flow rates for extended periods.

Implementation Method 1

configured for mass transfer by dialysis

Methodology Applied
Scientific EffectDialysis: Diffusion

Implementation Method 2

Mass transfer rates through membranes in conventional systems may be affected by diffusion rates through the relatively thick boundary layer

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

Increasing fluid velocity near the membrane surface, for example by stirring, is a common method of decreasing the boundary layer thickness, thus the effective diffusion length

Methodology Applied
Scientific EffectBoundary layer reduction: Boundary Layer

Implementation Method 4

a fifth lamina is positioned over the fourth lamina such that the fourth via of the fourth lamina is sealed by the compression of the compression seal between the fifth lamina and the fourth lamina

Methodology Applied
Scientific EffectCompression sealing: Compression

Data Source

PatentEP2445615B1Microfluidic devices for dialysis
Publication Date: 2017.05.17 OUTSET MEDICAL
  • EP2445615B1 patent drawingFigure 1~2
  • EP2445615B1 patent drawingFigure 3~4
  • EP2445615B1 patent drawingFigure 5~6A

AI summary

The present disclosure concerns embodiments of a microfluidic transfer device. The device mitigates risk of cross contamination between working fluids and is amenable to high-volume, low-cost manufacturing techniques. The device may be configured for mass transfer, heat transfer, or both. For instance, certain disclosed embodiments incorporate semi-permeable membranes to transfer target substances from one fluid to another. Moreover, the device may incorporate both heat and mass transfer components.