Cross-Channel Fluid Mixer for Exponential Concentration Gradients
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Solution Overview
Problem
Conventional fluid mixing devices require high electrical driving forces, are not portable, and struggle to produce exponential concentration gradients efficiently, especially in microfluidic chip systems used for serial dilution.
Innovation Solution
A fluid mixing device with a crossing channel structure that utilizes pressure differences and varying numbers and sizes of via holes at intersections to produce solutions with different concentrations without requiring additional electrical driving force, allowing for the creation of exponential concentration gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrokinetic driving is used in microfluidic devices, then fluid mixing can be achieved, but high voltage (400-1600 V) is required making the device non-portable
Solution Approach 1:
The patent replaces the electrical driving system (electrokinetic driving requiring 400-1600 V) with a mechanical pressure-driven system. The fluid mixing is achieved by applying pressure differences through the chip structure, eliminating the need for high voltage power supplies and making the device portable.
Solution Approach 2:
The patent employs pressure-driven fluid flow through the microchannel structure, using pneumatic or hydraulic pressure sources to drive the sample solution and diluent through the channels and mixing regions, replacing electrical actuation with pressure-based actuation.
2Productivity
If simple inter-diffusion of laminar flows is used, then device structure is simple, but it takes a long time to form a concentration gradient
Solution Approach 1:
The patent incorporates curved or serpentine channel designs instead of straight linear channels. The curved paths increase the diffusion path length and create more mixing opportunities, significantly accelerating the formation of concentration gradients while maintaining a relatively simple planar chip structure.
Solution Approach 2:
The patent introduces vertical mixing elements or multi-layer channel structures that add a third dimension to the mixing process. This dimensional addition creates enhanced mixing surfaces and pathways, dramatically improving mixing speed without proportionally increasing the chip's footprint area.
3Manufacturing precision
If conventional microchannel mixing is used, then structure is simple, but only linear concentration gradient is achieved while exponential gradient is required
Solution Approach 1:
The patent varies the local properties of the mixing channels by changing the number, size, and distribution of via holes at different positions along the channel. This local variation in via hole configuration creates different mixing intensities at different locations, enabling the generation of exponential concentration gradients from a simple overall channel structure.
Solution Approach 2:
The patent employs asymmetric via hole arrangements where the number and size of via holes differ between left and right channels or between successive mixing stages. This asymmetry creates unequal mixing ratios that accumulate to produce exponential concentration gradients, transforming a simple symmetric structure into a precision gradient generator.
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 device is portable, efficient in producing a series of solutions with exponential concentration gradients, and capable of producing solutions with varying concentrations by controlling the number and size of via holes, enhancing the functionality of microfluidic systems.
Implementation Method 1
The inside of the second channels may be maintained at a higher pressure than the inside of the first channels. The sample solution flows in from the first channels into the second channels due to the difference in pressure at both ends of the via holes.
Implementation Method 2
Mixing by diffusion is formed between the two different groups of fluid paths.
Data Source
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AI summary
Provided is a fluid mixing device which produces a series of solutions with a concentration gradient. The fluid mixing device includes: a plurality of first channels (11) disposed parallel to each other on a layer, and into which an equal amount of diluent flows from its upstream; a plurality of second channels (21) formed perpendicular to the first channels on an adjacent layer to the layer on which the first channels are formed, and into which an equal amount of sample solution flows from its upstream; and via holes (25) formed at at least one intersection between each of the first channel and a plurality of second channels so that a predetermined amount of sample solution flows from the second channels into corresponding first channels, wherein a series of solutions with different concentrations is produced in the first channels depending on the amount of sample solution that flows into the first channels through the via holes. Thus, a series of solutions with different concentrations is output from the first channels.