Plasma Separation Substrate With Slot Flexures
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Solution Overview
Problem
Existing devices for plasma separation and collection from blood samples face challenges in accurately holding and positioning two membranes end-to-end, requiring high manufacturing tolerance and uniform pressure application, which is not compatible with low-cost methods like injection molding and can damage the membranes.
Innovation Solution
A substrate with inner and outer flexures formed by slots, allowing for precise alignment and pressure application between the separation and collection membranes, facilitating consistent plasma transfer without membrane damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate membranes are used for separation and collection of plasma, then the functionality is improved (separation and collection can be performed simultaneously with different materials/chemistries), but the device complexity increases (requiring precise end-to-end alignment and overlap)
Solution Approach 1:
The distal end of the first membrane is inserted into a recess formed at the proximal end of the second membrane, creating a nested configuration. This nesting approach eliminates the need for complex external alignment mechanisms while maintaining precise end-to-end contact between the two membranes, thus reducing device complexity while preserving functionality.
Solution Approach 2:
A recess structure acts as an intermediary element that receives and secures the distal end of the first membrane. This intermediary feature facilitates precise positioning and stable contact between the two membranes without requiring high manufacturing tolerances in the membranes themselves, thereby simplifying the overall device while maintaining functional performance.
2Manufacturing precision
If high manufacturing tolerance is required for membrane alignment, then the alignment precision is improved, but the ease of manufacture deteriorates (incompatible with low-cost methods like injection molding)
Solution Approach 1:
The recess is pre-formed in the second membrane during the manufacturing process, creating a built-in alignment feature. This preliminary action eliminates the need for post-manufacturing alignment adjustments and allows the use of low-cost injection molding methods while achieving consistent, precise membrane positioning through the integrated recess structure.
Solution Approach 2:
The design changes the alignment approach from requiring high precision in membrane dimensions to using a geometric feature (recess) that inherently provides alignment. This parameter change allows manufacturing with standard tolerances using injection molding, as the recess geometry compensates for variations in membrane dimensions while maintaining precise end-to-end contact.
3Reliability
If uniform pressure is applied at the contact area of membranes, then the plasma transfer consistency is improved, but the risk of membrane damage increases
Solution Approach 1:
The recess structure creates a localized contact area with optimized pressure distribution. By confining the contact to the recess region rather than a broad flat interface, the design achieves uniform pressure application exactly where needed for plasma transfer while distributing stresses to avoid concentrated loads that could damage the membranes.
Solution Approach 2:
The recess structure acts as a cushioning element that absorbs and distributes applied pressure before it reaches the membrane contact interface. This beforehand cushioning effect ensures uniform pressure distribution across the contact area, maintaining consistent plasma transfer while protecting the membranes from damage due to pressure concentration or application errors.
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 substrate design enables accurate and reproducible alignment of membranes, ensuring efficient plasma separation and collection while being compatible with low-cost manufacturing methods and minimizing membrane damage.
Implementation Method 1
the outer flexure is configured to apply pressure on the separation and collection membranes about the overlapping contact area
Implementation Method 2
as the blood sample flows through, blood cells may be separated from the plasma based on the size of the membranes pores
Data Source
Figure 1
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Figure 3~4
AI summary
A substrate (100) for positioning a separation membrane (152) and a collection membrane (154) for separating and collecting plasma is disclosed. The substrate includes an inner flexure (102) disposed proximate to a first peripheral portion of the substrate and an outer flexure (104) disposed surrounding at least a portion of the inner flexure. The inner flexure is formed from a plurality of first slots in the substrate and the outer flexure is formed from a plurality of second slots in the substrate.