Tilted Blister Pusher for Bubble-Free Microfluidic Reagent Release
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Solution Overview
Problem
Existing microfluidic blister opening systems often inject air bubbles into the circuit when releasing reagents due to the deformation of dome-shaped blisters, which can lead to operational issues and inefficiencies, and prior solutions like venting membranes are complex and unsuitable for mass production.
Innovation Solution
A blister opening system with a novel pusher and blister design that uses a tilted impelling surface to create a gas entrapment volume opposite the fluidic outlet channel, minimizing bubble injection by optimizing the angle between the pusher and support surface, and incorporating a notch to prevent backflow and channel collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dome-shaped blister is deformed by a cylindrical pusher to release reagents, then the reagents are effectively forced out into the microfluidic circuit, but air bubbles are injected into the circuit
Solution Approach 1:
The pusher header is designed with an asymmetric flat shape instead of a symmetric dome shape, with a specific orientation angle relative to the blister normal. This asymmetric geometry creates an air entrapment volume that prevents bubbles from entering the fluidic outlet channel while maintaining effective reagent release
Solution Approach 2:
The solution introduces a new dimensional parameter - the orientation angle of the pusher header relative to the blister normal - which was not considered in conventional cylindrical pushers. By optimizing this angular dimension, the system achieves both effective reagent release and air bubble prevention
2Object-generated harmful factors
If a rib surrounds the top surface of the dome-shaped blister to control folding, then air is entrapped in the structure, but the rib collapses under high deformation causing air injection
Solution Approach 1:
The air entrapment function is extracted from the structural rib and integrated into the pusher header geometry itself. The flat header with optimized orientation creates the air entrapment volume directly during the pushing action, eliminating the need for a separate rib structure that would require high mechanical strength
3Object-generated harmful factors
If a concave plunger head is used to form a bubble-trapping region, then some bubbles are trapped, but some bubbles still escape into the microfluidic circuit
Solution Approach 1:
The pusher header design creates a localized air entrapment volume with specific geometric properties oriented at an optimal angle. This local geometric configuration ensures that air is trapped in a controlled region that is spatially separated from the fluidic outlet channel, providing reliable bubble-free operation
Solution Approach 2:
The pusher header geometry is pre-configured with the optimal orientation angle before contact with the blister. This preliminary geometric arrangement ensures that as the pusher contacts and deforms the blister, air is automatically directed into the entrapment volume and prevented from entering the outlet channel from the outset
4Object-generated harmful factors
If permeable membranes are used to vent air bubbles, then gas can be vented, but small amounts of gas bubbles are still injected and the system becomes more complex
Solution Approach 1:
The pusher header itself performs the air entrapment and bubble prevention function through its geometric design and orientation. No separate venting membrane or additional component is needed - the header's flat shape and orientation angle create the air entrapment volume that automatically prevents bubble injection, simplifying the overall system
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 effectively dispenses over 80% of the liquid volume without injecting gas bubbles into the microfluidic circuit, improving operational efficiency and reducing bubble-related issues compared to prior systems.
Implementation Method 1
the header is adapted for being movable relative to the blister body and to transmit, with said relative movement, a pressure against the blister body through the impelling surface
Implementation Method 2
the pressure of the impelling surface against the blister body configures a gas entrapment volume in the blister body, wherein said gas entrapment volume is arranged substantially at an opposite side of the blister body with regard to the fluidic outlet channel
Data Source
AI summary
This invention relates to a blister opening system comprising a blister body (1) arranged over a support surface (1′″); a header (2) comprising an impelling surface (2′), wherein said header (2) is movable relative to the blister body (1) and transmits a pressure against the blister body (1) through the impelling surface (2′) in a pushing direction (3); and a fluidic outlet channel (4) fluidically connected to the blister body (1). The system is characterized in that the impelling surface (2′) is arranged such that, in a relative position between the header (2) and the blister body (1) the pushing direction (3) and the support surface (1′″) form a relative angle (5) substantially different from 90°. The pressure of the impelling surface (2′) against the blister body (1) configures a gas entrapment volume (1″) at an opposite side of the blister body (1) with regard to the fluidic outlet channel (4).