Microfluidic Mixing Device Using Bellows Pumps for Turbulent Flow
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Solution Overview
Problem
Microfluidic devices face limitations in mixing larger analytes such as cells, bacteria, and macromolecular complexes due to slow diffusional mixing, which hinders bulk mixing or combination of samples and reagents, especially in the laminar flow regime characteristic of these devices.
Innovation Solution
The implementation of a microfluidic mixing device utilizing a pair of bellows pumps with elastomeric membranes and a network of microchannels that alternate between laminar and turbulent flow, promoting efficient mixing by creating fluid jets and vortices that increase the surface area for interaction between solutions of different viscosities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diffusion-based mixing is used in laminar flow regime, then mixing of small molecules is effective, but mixing of larger analytes such as cells, bacteria, and macromolecular complexes is slow
Solution Approach 1:
The patent applies dynamic flow regime transitions by alternating between laminar and turbulent flow conditions through periodic actuation of the bellows pumps. This dynamic switching enables the system to leverage diffusion effectiveness during laminar phases while achieving rapid bulk mixing during turbulent phases, thereby resolving the contradiction between mixing effectiveness and mixing time for different analyte sizes
Solution Approach 2:
The patent changes the flow regime parameter by transitioning between laminar and turbulent flow states. The bellows pump actuation frequency and amplitude are adjusted to control Reynolds number variations, enabling the fluid to switch between flow regimes. This parameter change allows the system to optimize mixing for both small molecules (diffusion-dominated in laminar flow) and large analytes (convection-enhanced in turbulent flow)
2Device complexity
If conventional microfluidic mixing is used, then device simplicity is maintained, but bulk mixing or combination of sample and reagents is limited
Solution Approach 1:
The patent employs pneumatic actuation through bellows pumps to generate the alternating laminar and turbulent flow regimes. The elastomeric membranes are actuated by pneumatic pressure to create reciprocating pump motion, which drives the dynamic flow conditions necessary for enhanced mixing. This pneumatic mechanism enables efficient bulk mixing while maintaining a relatively simple device structure that can be integrated into standard microfluidic platforms
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 enhances the mixing of biological samples and reagents by transitioning between laminar and turbulent flow, accelerating the interaction and integration of solutions with different viscosities, thereby improving the preparation and analysis of biological samples.
Implementation Method 1
a first bellows pump with a chamber bisected in coronal plane by a first elastomeric membrane, a second bellows pump with a chamber bisected in coronal plane by a second elastomeric membrane
Implementation Method 2
the laminar flow channel has a depth sufficiently small to allow laminar flow of the streams
Implementation Method 3
utilizing a pair of bellows pumps with elastomeric membranes and a network of microchannels that alternate between laminar and turbulent flow, promoting efficient mixing by creating fluid jets and vortices
Implementation Method 4
Smaller particles, such as ions or small proteins, diffuse rapidly across the fluid boundaries
Data Source
AI summary
A microfluidic mixing device comprising two bellows pumps (105, 115), microfluidic cartridges comprising the same and methods for use of the same are provided. The disclosed device enables efficient mixing of samples at the microfluidic scale. More particularly, the microfluidic mixing device comprises: a first bellows pump (105); a second bellows pump (115); a first microchannel fluidly interconnecting the first bellows pump (105) with a sample inlet and a reagent reservoir, wherein the first microchannel comprises a valve (V10) interposed between the pump and the inlet, and a valve (V1) interposed between the pump and the reservoir; a second microchannel fluidly interconnecting the first bellows pump (105) with the second bellows pump (115), wherein the second micro channel comprises a valve (V11) interposed between the first and second pump; a third microchannel fluidly interconnecting the first bellows pump (105) with the second bellows pump, wherein the third micro channel comprises a valve (V11) interposed between the first and second pump; a first and second pneumatic member pneumatically connected to the first and second bellows pumps; wherein, the volume of the second bellows pump (115) is greater than the volume of the first bellows pump (105).