Microchannel Constriction for Concentrating Charged Objects
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Solution Overview
Problem
Existing methods for concentrating electrically charged molecules and objects in solution, such as those using nanochannels with ion selectivity, are limited by low flow rates and restrictive salinity conditions, and lack the ability to efficiently separate deformable objects like DNA or cells without causing mechanical stress.
Innovation Solution
A method involving a channel with a constriction that applies a hydrodynamic flow and an electric field to concentrate electrically charged objects in a non-Newtonian fluid, allowing for higher flow rates and flexible salinity conditions, and enabling the separation of objects based on size and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ion-selective nanochannels are used for concentrating molecules, then separation capability is improved, but flow rate is limited to very low values
Solution Approach 1:
The invention changes the physical parameters of the system by replacing nanoscale ion-selective channels with microscale parallel channels that have different cross-sectional dimensions. This parameter change allows the system to operate at much higher flow rates while maintaining separation capability through the combined effect of hydrodynamic flow and electric field across multiple parallel pathways.
Solution Approach 2:
The invention segments the flow path into multiple parallel channels with different cross-sectional dimensions. This segmentation allows simultaneous processing of multiple sample streams at higher flow rates, overcoming the single-channel bottleneck of nanochannel systems while maintaining separation resolution through dimension-based differential migration.
2Measurement precision
If ion-selective nanochannels are used for concentrating molecules, then separation capability is improved, but salinity conditions are restricted
Solution Approach 1:
The invention creates a universal concentration system that functions across diverse salinity conditions by relying on fundamental electrophoretic and hydrodynamic principles rather than ion-selective membrane properties. The parallel channel structure with dimension-based separation is adaptable to various buffer compositions and ionic strengths, making the system versatile for different sample types.
3Productivity
If high flow rates are applied in conventional channels, then productivity is improved, but concentration efficiency decreases due to insufficient field modulation
Solution Approach 1:
The invention applies local quality by creating regions of different cross-sectional dimensions within the parallel channel structure. This dimensional variation locally modulates the electric field and hydrodynamic flow characteristics, enabling effective concentration and separation even at high overall flow rates. Each channel dimension is optimized for specific separation requirements.
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 allows for efficient concentration and separation of electrically charged molecules and objects at higher flow rates, suitable for large-scale samples, without salinity restrictions, and can handle both deformable and non-deformable objects, including DNA, proteins, and cells, with a short concentration period and simple implementation.
Implementation Method 1
applying a hydrodynamic flow in one direction of said channel together with applying an electric field in the opposite direction in said channel, making it possible to move the electrically charged objects in the channel along the flow axis
Implementation Method 2
applying an electric field in the opposite direction in said channel, making it possible to move the electrically charged objects in the channel along the flow axis from the first section to the second section and to stop and concentrate them
Implementation Method 3
the second cross-section forms a constriction which makes it possible to spatially modulate the hydrostatic and electric fields so as to stop the movement of the objects at a predetermined location
Data Source
Figure 1~2
Figure 3~5
Figure 6A~6B
AI summary
The invention relates to a method for concentrating electrically charged objects in a non-Newtonian liquid medium. Said method includes: - feeding a sample, containing electrically charged objects, into a channel having a flow axis (14), a first transverse cross-section orthogonal to the flow axis, and at least one second transverse cross-section orthogonal to the flow axis, one dimension of said second cross-section being less than the corresponding dimension of said first cross-section; and - applying a hydrodynamic flow in a direction of said channel together with the application, in the opposite direction, of an electrical field in said channel, thus making it possible to move the electrically charged objects in the channel along the flow axis (14) from the first cross-section to the second cross-section, stop said objects, and concentrate said objects in at least one area upstream from said second transverse cross-section.