Microfluidic Activation Mechanism with Pressure Balancing
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Solution Overview
Problem
The existing SIMPLE microfluidic pumping technology faces issues with user-dependent actuation forces leading to pressure imbalances and backflow, as well as evaporation of working liquids during storage, which affects the stability and reproducibility of fluid displacement.
Innovation Solution
A fluid conduit device with a capillary pump and a pressure release channel that directs excess working liquid into a liquiphilic porous blocking vent, preventing pressure build-up and allowing for robust activation, while a pressure compensation channel manages pressure imbalances after actuation, and a permanent pressure source or external container maintains liquid volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single fingertip press is used to activate the SIMPLE pump, then the device can be activated with simple operation, but the actuation force becomes user-dependent leading to pressure imbalances and backflow
Solution Approach 1:
The patent employs a porous valve member that can be in either an open or closed state. When closed, it prevents communication between the activation chamber and the first microchannel, thereby preventing backflow of working liquid to the upstream fluidic channel. This porous material-based valve mechanism provides reliable pressure balancing while maintaining simple fingertip activation operation.
2Adaptability or versatility
If working liquid is pre-stored within the chip, then the system is compact and ready-to-use, but evaporation occurs during storage reducing liquid volume and increasing activation difficulty
Solution Approach 1:
The patent extracts the working liquid from the main fluidic system by providing a separate liquid storage container that is disconnected from the microfluidic network during storage. The working liquid is loaded into this external container, which prevents evaporation from occurring in the open microchannels. Upon activation, the liquid is then introduced into the system, maintaining both ready-to-use capability and preventing substance loss during storage.
3Device complexity
If the activation chamber retains its original shape after pressure source removal, then the chamber structure is simple, but abrupt negative pressure is introduced causing disconnection of working liquid from porous pump material
Solution Approach 1:
The patent applies preliminary action by providing a biasing element that pre-loads the activation chamber wall in a bowed state. This biasing element automatically compensates for pressure changes when the pressure source is removed, preventing the chamber from returning to its original shape and thereby preventing abrupt negative pressure that would disconnect the working liquid from the porous pump material.
4Ease of operation
If the working liquid front is positioned close to the porous substrate, then activation is easier with smaller pressure differences, but the device is more sensitive to evaporation and spontaneous activation during storage
Solution Approach 1:
The patent extracts the working liquid from the microfluidic network during storage by using a separate liquid storage container. This allows the working liquid front to be positioned further away from the porous substrate without risking spontaneous activation, while still enabling easy activation when needed by introducing the liquid into the system.
Solution Approach 2:
The patent applies preliminary action by pre-loading the liquid storage container with the working liquid before use. This preliminary preparation allows the liquid to be introduced into the microfluidic system at the appropriate time, maintaining both storage stability and ease of activation.
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 ensures robust and reproducible fluid displacement with reduced evaporation effects, preventing backflow and maintaining stable pressure, thus enhancing the reliability of microfluidic systems.
Implementation Method 1
a pressure release channel, having between said pressure release channel and said porous pump element a liquiphilic porous blocking vent
Implementation Method 2
the conduit being operationally connected to the inlet of the capillary pump
Implementation Method 3
a capillary pump, comprising a solid sorbent enclosed in an enclosure and having an inlet and an outlet
Implementation Method 4
separated from upstream fluidic elements by a liquiphobic barrier which is permeable to air but retains liquids
Data Source
AI summary
In general, the disclosure relates to a fluid conduit device, such as microfluidic technique, with minimal operation. More specifically, the present invention relates to an activation and pressure balancing mechanism suitable for robust activation of fluid conduit devices.