Microchip Asymmetric Flow Path Width Prevents Reverse Flow
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Solution Overview
Problem
Existing microchips for DNA analysis face issues with sample leakage due to reverse flow, which is not effectively prevented by conventional reverse flow prevention valves.
Innovation Solution
A microchip design featuring laminated elastic sheets with asymmetric flow path widths, where a narrower flow path width at the connecting section prevents reverse flow by requiring a stronger force to flow liquid into the first flow path compared to the second flow path, and a reverse flow preventing structure that allows liquid transfer from the first flow path to the second but not vice versa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse flow prevention valve is equipped on tubes for transferring pressurizing medium, then reverse flow of sample is prevented, but sample leakage still occurs when sample flows reverse to the valve
Solution Approach 1:
The flow path width at the connecting section on the first flow path is made narrower than the flow path width at the connecting section on the second flow path. This asymmetric design creates different flow resistance characteristics that prevent reverse flow of sample while maintaining forward flow capability, eliminating the need for additional reverse flow prevention valves and their associated leakage risks.
2Reliability
If conventional reverse flow prevention valves are used, then reverse flow is partially prevented, but sample leakage occurs at the valve or before it
Solution Approach 1:
The narrow flow path width is specifically implemented at the connecting section between the first and second flow paths, while other sections maintain their original dimensions. This localized asymmetric design creates a flow resistance barrier precisely where needed to prevent reverse flow, minimizing sample loss without affecting overall system performance.
3Ease of manufacture
If symmetric flow path widths are used in connecting sections, then manufacturing is simplified, but reverse flow prevention is insufficient
Solution Approach 1:
The connecting section of the first flow path is designed with a narrower width compared to the connecting section of the second flow path. This asymmetric configuration creates inherent directional flow control through differential resistance, providing reliable reverse flow prevention while remaining compatible with standard microfabrication processes.
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 microchip effectively prevents sample leakage by ensuring that the liquid flows unidirectionally, reducing the risk of reverse flow and sample loss during DNA analysis processes.
Implementation Method 1
a flow path width at the connecting section on the first flow path is narrower than a flow path width at the connecting section on the second flow path
Data Source
AI summary
A microchip includes a plurality of laminated elastic sheets. Each of the elastic sheets forming a first intermediate layer as an intermediate layer formed with the plurality of elastic sheets have an inadhesive section(s) for forming a first flow path on the first intermediate layer. Each of the elastic sheets for forming a second intermediate layer as an intermediate layer formed with the plurality of elastic sheets have an inadhesive section(s) for forming a second flow path on the second intermediate layer. An elastic sheet(s) interposed between the first and second intermediate layers has a connecting section(s) connecting the first flow path and the second flow path. A flow path width at the connecting section(s) of the first flow path is narrower than a flow path width at the connecting section(s) of the second flow path.