In-Situ Fluidic Inspection for Microfluidic Seal Integrity
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Solution Overview
Problem
Microfluidic devices face issues with unreliable seals between the instrument, flowcell, and cartridge, leading to failed runs and potential damage to electronic components due to liquid leakage, and require an in-situ method to test seal integrity and accurately establish the home position of the rotary valve.
Innovation Solution
An in-situ inspection method using a flow sensor and pressurized air to test the integrity of seals between the instrument and cartridge components, including the rotary valve, flowcell, and syringe pump, while correcting for hysteresis and backlash, and determining the fluidic center alignment within ±1 degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seals are made tighter to prevent liquid leakage, then reliability is improved, but device complexity increases due to additional sealing components and assembly steps
Solution Approach 1:
The system performs self-diagnosis by using the existing fluidic pathways to automatically test seal integrity through pressure differential measurement. The cartridge itself serves as the testing apparatus, eliminating the need for external seal testing equipment or additional sealing components.
Solution Approach 2:
The invention uses pneumatic pressure differentials to test seal integrity. By pressurizing the air pathway and measuring flow through the fluidic centering assembly, the system detects seal leaks without requiring additional sealing mechanisms, leveraging fluid dynamics to accomplish both sealing and testing functions.
2Reliability
If in-situ seal testing is implemented, then reliability is improved by detecting seal issues before runs, but device complexity increases due to additional testing components
Solution Approach 1:
The fluidic centering assembly serves dual purposes: it performs both fluidic alignment and seal integrity testing. The same pathways and components used during normal operation are utilized for testing, eliminating the need for separate testing hardware and reducing overall device complexity.
Solution Approach 2:
The system tests its own seals using its existing operational pathways. By flowing air through the same channels used for reagent delivery and measuring pressure differentials, the cartridge performs self-diagnosis without requiring external testing equipment or additional components.
3Measurement precision
If fluidic centering is performed to establish home position, then measurement precision is improved, but time is lost during the centering process
Solution Approach 1:
The system performs fluidic centering as a preliminary step before actual operation. By establishing the home position and verifying seal integrity upfront, the system prevents time loss during runs due to misalignment or seal failures. The air flow test simultaneously verifies both centering and seal status.
Solution Approach 2:
The fluidic pathways remain active during centering and testing, maintaining continuous useful action. The same channels used for reagent delivery are used for air flow testing, ensuring that the centering process does not require separate, time-consuming setup steps but rather integrates seamlessly into the operational sequence.
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 method effectively tests seal integrity and accurately establishes the home position of the rotary valve, ensuring reliable operation and preventing damage by identifying and correcting seal-related issues, thereby enhancing the functionality and longevity of microfluidic devices.
Implementation Method 1
The mass flow of air through the flow path is measured with the flow sensor
Implementation Method 2
A source of pressurized air is connected to the flow sensor in order to establish a mass flow of air through a flow path
Data Source
AI summary
A method includes engaging a well of a cartridge with a flow sensor of an instrument. The cartridge includes: a rotary valve including a rotatable port and a center port; the well in fluid communication with a channel, the channel including a channel port that the rotatable port is to align to in order to receive fluid from the well; and a flowcell including an inlet gasket in fluid communication with the center port. A source of pressurized air is connected to the flow sensor in order to establish a mass flow of air through a flow path. The flow path extends through one of the flow sensor, the channel, the rotary valve, and the flowcell. The mass flow of air through the flow path is measured with the flow sensor. It is determined if there is one of an air leak and an air blockage within the flow path.