Microfluidic Coflow Device for Laminar Flow Control
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Solution Overview
Problem
In microfluidic devices, the parabolic velocity profile caused by channel walls leads to broadening of radial velocity distribution with increasing channel length, making it difficult to control reaction time accurately in time-resolved reactions.
Innovation Solution
A coflow generator and separator system is used to create a concentric coflow pattern in the tubing, where the buffer solution flows adjacent to the wall and the reaction mixture at the center, reducing the parabolic velocity profile by controlling the flow rates and buffer solution width, thereby bounding the mixture without contact with the wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the channel length is increased to allow sufficient reaction time, then the reaction can be completed, but the radial velocity distribution broadens due to parabolic velocity profile
Solution Approach 1:
The reaction mixture is segmented from the channel wall by introducing a buffer solution that forms a concentric co-flowing layer. This segmentation isolates the mixture core from the wall-induced parabolic velocity profile, allowing the mixture to maintain a more uniform velocity distribution throughout the reaction channel.
Solution Approach 2:
The buffer solution acts as an intermediary substance between the reaction mixture and the channel wall. It absorbs the harmful effect of the parabolic velocity profile by flowing adjacent to the wall, while allowing the mixture to flow through the center with a flattened velocity distribution.
2Speed
If the channel wall creates drag to control flow, then the velocity is regulated, but the parabolic velocity profile causes dispersion of the mixture
Solution Approach 1:
The buffer solution serves as an intermediary that mediates between the wall drag and the reaction mixture. It experiences the wall drag and converts it into a flattened velocity profile for the inner mixture core, thereby maintaining velocity uniformity while still controlling overall flow rate.
Solution Approach 2:
The system changes the velocity distribution parameter by introducing the buffer solution with a different flow rate ratio. By adjusting the buffer-to-mixture flow rate ratio, the velocity profile of the mixture can be flattened while maintaining controlled overall flow through the channel.
3Ease of operation
If the mixture contacts the channel wall, then the flow is bounded, but the wall creates drag and broadens velocity distribution
Solution Approach 1:
The buffer solution acts as an intermediary that provides flow bounding for the mixture without direct contact between the mixture and channel wall. The buffer solution absorbs the wall interaction, allowing the mixture to be contained while avoiding wall-induced drag and velocity profile broadening.
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 narrows the reaction time dispersion, allowing for precise control and accurate time-stamping of reactant states, facilitating high-resolution imaging of short-lived intermediates in applications like cryo-Electron Microscopy.
Implementation Method 1
the mixture and the buffer solution can flow in a laminar state in the tubing, by controlling the flowrate of the reaction mixture or the bugger solution
Data Source
AI summary
The present subject matter relates to devices and techniques for reducing the parabolic velocity profile. The disclosed device can include a coflow generator configured to receive a buffer solution and a mixture of at least two components to form a coflow pattern in a tubing, and a coflow separator configured to seperate the buffer solution from the reaction mixture. The coflow generator and the coflow separator can be coupled through the tubing. The tubing can be configured to receive the mixture and the buffer solution from the coflow generator and have the mixture bounded by the buffer solution without contacting a wall of the tubing.