Patterned Thermoplastic Elastomer Film for Microfluidic Blister Sealing
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Solution Overview
Problem
Current microfluidic blisters face challenges in achieving controlled fluid release due to unreliable seals, particularly when dealing with low volumes, which can lead to leakage and contamination, and existing solutions complicate design and increase costs.
Innovation Solution
A patterned film with a regular polygonal tiling design for the gating region, composed of thermoplastic elastomer, which allows for controlled fluid release by focusing pressure onto a small subset of compartments, ensuring predictable debonding and minimizing wall-to-wall interaction, thus improving sealing and bursting control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuously applied external pressure is used to form the seal, then sealing reliability is improved, but device complexity and parts count increase
Solution Approach 1:
The patent extracts the sealing function from a separate continuously applied pressure mechanism and integrates it into the blister seal structure itself. The patterned gate region with walls and compartments creates inherent sealing zones that function without external continuous pressure, thereby reducing device complexity while maintaining sealing reliability.
Solution Approach 2:
The blister seal structure serves its own sealing function through its patterned gate region design. The walls and compartments create capillary sealing zones that automatically seal fluid pathways without requiring external continuous pressure application, making the system self-sufficient and reducing overall device complexity.
2Ease of operation
If a breakable seal is used to gate the blister, then fluid release control is enabled, but accidental failure risk increases
Solution Approach 1:
The gate region is segmented into multiple compartments separated by walls, creating multiple independent sealing zones. This segmentation ensures that fluid release requires simultaneous failure of multiple seals, dramatically reducing accidental failure risk while maintaining controlled release capability when intentionally activated.
Solution Approach 2:
The patterned gate region design inherently provides redundancy against accidental activation. The multiple walls and compartments create a buffered sealing system that requires significant and coordinated stress to fail, cushioning against premature or accidental fluid release while allowing controlled release when needed.
3Reliability
If tighter seals are used for fluid retention, then fluid leakage is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patterned gate region introduces local variation in seal geometry with walls and compartments of specific dimensions. This local quality design creates capillary sealing zones that enhance sealing performance through surface tension effects, allowing tighter effective seals without proportionally increasing overall manufacturing precision requirements.
Solution Approach 2:
The seal structure combines the blister membrane material with the patterned gate region geometry to create a composite sealing system. The patterned structure adds functional sealing capability through its geometric configuration rather than relying solely on material properties, reducing the burden on material fabrication tolerance while achieving tighter effective seals.
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 solution provides reliable and controlled fluid release with reduced risk of accidental failure, maintaining seal integrity and allowing for lower fabrication tolerances, thereby simplifying the fabrication process and reducing material complexity.
Implementation Method 1
focusing pressure onto a small subset of compartments
Implementation Method 2
each wall has a mean thickness that is less than a mean height, and each pair of walls has a mean separation greater than the mean thickness, providing space for deformation of the wall under pressure to facilitate controlled release
Data Source
Figure 1a~3d
Figure 4a~6f
Figure 7~9
AI summary
A patterned thermoplastic elastomer TPE film (10) for fabricating a liquid-filled blister, has a blister-sized cavity (15) in fluid communication with a microfluidic channel (16) via a gating region (14). The gating region is defined by a relief pattern that has at least one of the following: at least 5 separate compartments (20) defined by respective recesses in the first side, each of the recesses bounded by walls (22) that separate the compartments from each other, the recess, or the channel; at least 5 walls defined by the patterning of the first side, the walls separating a plurality of compartments from each other, the recess, or the channel, wherein the walls have a mean thickness that is less than a mean height, and each pair of walls has a mean separation greater than twice the mean thickness; an array of separate compartments bounded by walls defined by the patterning of the first side that collectively define a polygonal regular planar tiling with at least 50% of the surface area of the gating region being open spaces; and a focusing region (16a) in fluid communication with the cavity (15), and a seal region having at least one wall defined by patterning of the film, wherein the at least one wall separates the focusing region from the seal region, and a shape of the at least one wall tapers the focusing region towards the seal region.