Centrifugal Microfluidic Mixing Chamber with Deflection Element

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Solution Overview

Problem

Centrifugal microfluidic devices face inefficiencies in mixing fluids due to the absence of turbulence, relying solely on diffusive mixing, which is a slow process at the microfluidic scale, and existing methods from traditional microfluidics are not suitable, leading to prolonged mixing times.

Innovation Solution

A centrifugal microfluidic device with a microfluidic mixing chamber where fluid flows from separate channels are redirected to land at the same point on a mixing surface using a deflection element, enhancing diffusive mixing through flow discretization and alternate stacking of fluids, allowing for almost instantaneous mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diffusive mixing is used in centrifugal microfluidic devices, then mixing is achieved without turbulence, but mixing time becomes excessively long

Engineering Contradiction:
Improvemixing effectivenessVSAvoidmixing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the fluid flow into discrete droplets that are injected sequentially into the mixing chamber. This segmentation creates multiple fluid interfaces and dramatically increases the effective surface area for diffusion, reducing mixing time from minutes to seconds while maintaining the passive diffusive mixing mechanism appropriate for centrifugal microfluidics

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs periodic injection of alternating fluid droplets from different channels into the mixing chamber. This periodic action creates a dynamic mixing pattern where fluids are continuously introduced and mixed in sequences, significantly enhancing mixing efficiency compared to continuous flow while still relying on diffusion

Inventive Principle:
Principle #19Periodic action

2Reliability

If traditional microfluidic mixing methods are transferred to centrifugal microfluidics, then mixing mechanisms are available, but device complexity and fabrication cost increase

Engineering Contradiction:
Improvemixing capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention utilizes the centrifugal field already present in the system to drive fluid injection and mixing. The centrifugal force naturally propels droplets from the channels into the mixing chamber and facilitates their mixing, eliminating the need for additional pumps, valves, or complex actuation mechanisms required in traditional microfluidic mixing approaches

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the flow regime parameter by operating in a regime where discrete droplet injection occurs under centrifugal force rather than continuous laminar flow. This parameter change enables effective mixing through a simpler mechanism that leverages the inherent centrifugal environment without requiring complex additional components

Inventive Principle:
Principle #35Parameter changes

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 approach significantly reduces diffusion lengths and times, achieving efficient and rapid mixing of fluids, independent of materials used and without increasing device complexity, making it suitable for various microfluidic applications.

Implementation Method 1

fluids are moved around the device through channels under the influence of a centrifugal field generated by rotation of the device around a rotation axis of a microfluidic platform

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

In such Reynolds number regimes the flow is always laminar, turbulences of any kind being completely forbidden. This is a serious drawback for mixing two or more liquids since, in the absence of any turbulence, diffusive mixing is the only available mechanism

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2814773B1Centrifugal microfluidic mixing apparatus and method
Publication Date: 2017.05.31 NAT RES COUNCIL OF CANADA
  • EP2814773B1 patent drawingFigure 1A~1C
  • EP2814773B1 patent drawingFigure 2A~2C
  • EP2814773B1 patent drawingFigure 3A~3C

AI summary

A centrifugal microfluidic device having a microfluidic mixing element with a microfluidic mixing chamber in which at least two flows emerging from channels into the chamber at separate places are redirected to land at substantially the same place on a mixing surface provides efficient mixing of two or more fluids in the chamber.