Microfluidic Device Hydrophilicity Gradient Bubble-Free Filling
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Solution Overview
Problem
Microfluidic devices face challenges in efficiently filling wells with dPCR reaction mixture without gas bubble entrapment and ensuring proper fluidic separation between wells, which affects the accuracy of diagnostic assays.
Innovation Solution
The microfluidic device features a flow channel with a first surface having a higher hydrophilicity than a second surface, optimizing the filling process by ensuring the fluid fills the wells faster than the flow channel, thus preventing gas bubble entrapment. Additionally, the device incorporates hexagonal wells with a specific aspect ratio and rounded edges to enhance filling and separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the flow channel is filled with dPCR reaction mixture by passive capillary forces, then the filling process is simple and requires minimal external intervention, but gas bubbles may be trapped in the wells and flow channel
Solution Approach 1:
The patent applies different hydrophilicity characteristics to different surfaces: the first flow channel surface is made more hydrophilic to promote liquid filling, while the second flow channel surface is made more hydrophobic to prevent bubble entrapment. This local differentiation of surface properties resolves the contradiction between simple capillary filling and reliable bubble-free operation.
Solution Approach 2:
The patent changes the surface energy parameters (hydrophilicity) of the flow channel surfaces to optimize the filling process. By adjusting the contact angle parameters through surface treatment or material selection, the system achieves both easy capillary filling and prevention of bubble entrapment.
2Reliability
If an immiscible separation or sealing fluid is pressed through the inlet opening to cover filled wells, then fluidic separation between wells is achieved and cross contamination is avoided, but the filling process becomes more complex and time-consuming
Solution Approach 1:
The patent performs preliminary surface treatment to create hydrophilic/hydrophobic patterns before the filling operation. This pre-prepared surface structure enables automatic fluidic separation through capillary action alone, eliminating the need for subsequent immiscible fluid injection and reducing process complexity.
Solution Approach 2:
The microfluidic device uses its own surface properties to achieve fluidic separation automatically. The hydrophobic second surface causes the liquid to naturally retract and seal at the well openings without requiring external separation fluids, making the system self-sufficient.
3Productivity
If the first flow channel surface is made more hydrophilic than the second flow channel surface, then the filling performance is improved and gas bubble entrapment is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The patent divides the flow channel into two distinct surfaces with different hydrophilicity characteristics. This segmentation allows each surface to be optimized independently for its specific function: the first surface for promoting filling and the second surface for preventing bubble entrapment, thereby managing manufacturing precision requirements through functional分区.
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 design improves the filling performance of the microfluidic device, prevents gas bubble entrapment, and ensures reliable fluidic separation between wells, leading to more accurate and reliable diagnostic assays.
Implementation Method 1
The first flow channel surface provides a first hydrophilicity and at least a part of the second flow channel surface provides a second hydrophilicity, wherein the first hydrophilicity is greater than the second hydrophilicity
Implementation Method 2
the dPCR reaction mixture is introduced by means of a pipette or the like into the inlet opening, and typically flows passively by capillary forces into the array of wells of the chip
Data Source
AI summary
A microfluidic device for thermocycling of a reaction mixture is provided. The device comprises an inlet opening, an outlet opening, a flow channel connecting the inlet opening and the outlet opening and defining a flow direction from the inlet opening through the flow channel to the outlet opening, wherein the flow channel comprises a first flow channel surface and a second flow channel surface opposite to the first flow channel surface, and an array of wells provided in the first flow channel surface for fluidic communication with the inlet opening and the outlet opening. Further, the first flow channel surface provides a first hydrophilicity and at least a part of the second flow channel surface provides a second hydrophilicity, wherein the first hydrophilicity is greater than the second hydrophilicity.