Flow Cell Taper Section Presses Sample Against Wall
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Solution Overview
Problem
Existing fluid delivery methods for flow cells often fail to ensure that a liquid sample is pressed onto the inner wall of the flow cell for clear imaging, as the sheath fluid can interfere between the sample and the imaging device, leading to poor image quality.
Innovation Solution
A fluid delivery method that utilizes a taper section in the flow cell with inclined inner walls to create a confluent flow path where the sheath fluid can press the liquid sample onto a specific inner wall, ensuring it flows in contact with the wall for clear imaging, by controlling the fluid delivery pressures of the sample and sheath fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If sheath fluid is delivered to press the liquid sample onto the bottom face of the flow cell, then the liquid sample should be flattened for imaging, but the sheath fluid is interposed between the liquid sample and the imaging device, making it difficult to clearly image the formed elements
Solution Approach 1:
Instead of pressing the sample onto the bottom face from above (conventional approach), the patent inverts the approach by pressing the sample onto the top inner wall from below. The sheath fluid flows along the bottom inner wall and presses the sample against the top inner wall, which is positioned closer to the imaging device. This inversion resolves the contradiction by achieving sample flattening while keeping the sample in contact with the imaging device rather than having sheath fluid interposed.
Solution Approach 2:
The patent changes the dimensional approach by utilizing the vertical dimension within the flow cell. Instead of horizontal pressing from above, the sheath fluid flows horizontally along the bottom wall and presses the sample vertically against the top wall. This dimensional change allows the sample to be flattened while maintaining proximity to the imaging device, resolving the contradiction between sample shape control and imaging quality.
2Ease of operation
If the liquid sample flows freely in the confluent flow path, then the flow is simple, but the liquid sample does not become pressed onto the bottom face, resulting in poor imaging
Solution Approach 1:
The patent applies local quality by creating different flow conditions in different regions of the confluent flow path. In the upstream region, the sample flows freely with simple flow characteristics. In the downstream region, the sheath fluid flows along the bottom wall to press the sample against the top wall, creating a localized pressing zone. This local differentiation maintains overall flow simplicity while achieving the necessary sample pressing for imaging.
Solution Approach 2:
The sheath fluid acts as an intermediary that enables sample pressing without requiring complex mechanical structures. By introducing the sheath fluid as a mediating substance that flows along the bottom wall and presses the sample against the top wall, the system achieves controlled sample positioning while maintaining simple operational procedures. The sheath fluid mediates between the simple flow requirement and the imaging quality requirement.
3Measurement precision
If a taper section with inclined inner walls is introduced to control sample pressing, then the sample can be pressed onto the inner wall, but the flow cell structure becomes more complex
Solution Approach 1:
The patent employs a taper section with inclined walls that create a gradual, curved transition rather than abrupt angular changes. This curved geometry guides the sheath fluid flow smoothly along the bottom wall and enables progressive sample pressing against the top wall. The curved/tapered structure achieves precise sample positioning while minimizing structural complexity compared to sharp-edged or multi-component designs.
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 method ensures the liquid sample flows in contact with the inner wall at the imaging position, facilitating clear observation and measurement by preventing sheath fluid interference, thereby improving image quality and measurement precision.
Implementation Method 1
delivering the sheath fluid into the sheath fluid flow path after the liquid sample reaches the measurement flow path and at a fluid delivery pressure greater than the fluid delivery pressure of the liquid sample, whereby the liquid sample and the sheath fluid flow on the second bottom face
Data Source
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AI summary
A fluid delivery method for delivering a liquid sample (70) to a flow cell (20) including a taper section (23C) including a first and a second inner walls (23E, 23F) opposing the first inner wall (23E), which is inclined to the second inner wall (23F) so that a distance between the first and the second inner walls (23E, 23F) at a downstream side of the taper section (23C) is shorter than a distance at an upstream side of the taper section (23C), and including measurement flow path provided downstream of the taper section (23C), through which a liquid sample (70) flows together with a sheath fluid (80). The fluid delivery method includes sample introduction of delivering the liquid sample (70) into the taper section (23C) along the second inner wall (23F) until the liquid sample (70) reaches the measurement flow path, and sample pressing by delivering the sheath fluid (80) into the taper section (23C) along the first inner wall (23E) after the liquid sample (70) reaches the measurement flow path.