Microfluidic Cartridge Passive Valve Pneumatic Control
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Solution Overview
Problem
Current microfluidic cartridge devices for multi-analyte analyses lack the ability to accurately measure multiple biological markers and are prone to cross-contamination, with challenges in maintaining vertical position leading to inaccuracies in fluid transfer.
Innovation Solution
A fluidic unit design featuring a chamber, venting port, and microfluidic channels with passive valves, utilizing gravity or centrifugal force to maintain fluid position and pneumatic pressure for precise fluid handling, including mixing, bubble removal, and serial dilution, integrated into a cartridge system that can be used for various biological tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pneumatic pressure is used to transfer fluid in microfluidic cartridges, then fluid transfer speed increases, but accurate volume transfer becomes difficult to control
Solution Approach 1:
The passive valve incorporates a pressure-sensing mechanism that automatically detects when the fluid level reaches the channel opening and stops flow accordingly. This feedback mechanism eliminates the need for external control systems while ensuring precise volume transfer, directly resolving the contradiction between fast pneumatic transfer and accurate volume control.
Solution Approach 2:
The passive valve design allows the fluid system to self-regulate its own flow termination based on the fluid level reaching the channel opening. The system serves itself by using the fluid's own presence to trigger the stop condition, eliminating the need for external sensors or control mechanisms and maintaining both speed and precision.
2Adaptability or versatility
If cartridges are designed for multi-analyte analysis, then testing capability increases, but cross-contamination risk increases
Solution Approach 1:
The cartridge is divided into multiple independent fluidic circuits, each with dedicated microfluidic channels and passive valves for specific analytes. This segmentation prevents cross-contamination between different test pathways while maintaining multi-analyte testing capability, as each circuit operates independently with its own fluid control mechanisms.
Solution Approach 2:
The cartridge is designed as a disposable single-use device that is discarded after one test run. This eliminates cross-contamination risk entirely by ensuring that each cartridge has never been used before, while still providing multi-analyte testing capability within that single-use unit.
3Device complexity
If gravity-dependent fluid transfer is used, then device complexity decreases, but accuracy is sensitive to tilting
Solution Approach 1:
The system uses pneumatic pressure applied through the venting port to drive fluid transfer instead of relying solely on gravity. This maintains relatively low device complexity while significantly improving accuracy by making fluid transfer independent of cartridge orientation and eliminating tilting sensitivity.
4Extent of automation
If passive valves are used in microfluidic channels, then automation increases, but difficulty in detecting fluid flow status increases
Solution Approach 1:
The passive valve incorporates visual indicators such as color-changing materials or contrasting colored components that change state or become visible when the valve opens or closes. This allows automated fluid flow control to be simultaneously detected visually, resolving the contradiction between automation and detectability.
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 fluidic unit ensures accurate and precise fluid transfer and handling, reducing cross-contamination risks and enabling multiple tests in a single cartridge, while compensating for tilting effects to maintain test accuracy.
Implementation Method 1
at least one passive valve located within the at least one microfluidic channel and configured to allow or stop fluid flow through the at least one microfluidic channel based on a pressure difference
Implementation Method 2
a venting port configured to apply a pneumatic force to the fluidic chamber
Implementation Method 3
The operation of this unit depends on gravity or another force as a replacement for gravity, such as a centrifugal force, to keep fluid in position
Implementation Method 4
another force as a replacement for gravity, such as a centrifugal force, to keep fluid in position
Data Source
AI summary
A method for analyzing biological samples is disclosed herein. In an embodiment, the method includes receiving a fluid sample into a cartridge device, which comprises: a fluidic chamber; at least one microfluidic channel in fluid communication with the fluidic chamber; and a venting port configured to apply a pneumatic force to the fluidic chamber; and inserting the cartridge device into a reader device to perform measurements, wherein the cartridge device is positioned in a vertical or tilted position such that at least a portion of the fluid sample inside the fluidic chamber is pulled by gravity in a direction away from the venting port or towards the bottom of the fluidic chamber.