Microfluidic Cartridge Gas Permeable Membrane Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microfluidic test methods face challenges in accurately tracking and stopping the flow of plasma samples within test cartridges, leading to inefficiencies and inaccuracies in measuring platelet activation energy, as the shear rate and stopping time are not consistently controlled, often resulting in sample wastage and prolonged testing times.
Innovation Solution
Incorporating a gas permeable membrane at the end of the imaging window in the microfluidic test cartridge to abruptly stop the forward momentum of plasma samples, allowing for precise control over sample shearing and imaging, enabling repeatable and rapid platelet imaging and reducing testing time by half compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual pump stopping is used to halt plasma flow, then sample flow can be stopped, but the sample continues to flow past the stopping point causing time waste and inconsistent shear rate control
Solution Approach 1:
A magnetic intermediary (magnetic bead coupled to the occlusion element) is introduced to mediate the interaction between the external magnetic field and the plasma sample. This intermediary enables precise control of plasma flow stopping through magnetic actuation, eliminating the imprecision of manual pump stopping and ensuring consistent shear rate control at the imaging window.
2Loss of substance
If manual pump stopping is used, then flow can be halted, but sample pushes completely out the microfluidic cartridge causing sample wastage
Solution Approach 1:
The system employs feedback control where an optical detector monitors plasma presence at the imaging window and provides signals to the magnetic actuator. This feedback loop enables precise stopping of plasma flow exactly at the desired location, preventing over-pushing of the sample out of the cartridge and eliminating sample wastage while maintaining ease of operation through automated control.
3Productivity
If rapid cartridge movement between imaging windows is performed, then testing time is reduced, but sample stability during imaging may be compromised
Solution Approach 1:
The magnetic occlusion element performs preliminary action by stopping plasma flow immediately before imaging at each window. This ensures the sample is stabilized and stationary in the imaging window before the imaging process begins, allowing rapid cartridge movement between windows without compromising sample stability during the actual imaging capture.
4Quantity of substance
If a single plasma sample is used for both baseline and agonist conditions, then sample quantity is reduced, but flow control and stopping precision must be improved
Solution Approach 1:
The patent replaces the mechanical pump stopping mechanism with a magnetic field-based occlusion system. This substitution enables precise control and stopping of plasma flow through magnetic actuation of the occlusion element, achieving the required flow stopping precision while using a single plasma sample for both baseline and agonist condition imaging.
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 solution ensures consistent and accurate preparation of samples for imaging, allowing for timely percent activation calculations and enabling the use of a single sample in different conditions, while preventing sample wastage and improving the accuracy of platelet aggregation measurements.
Implementation Method 1
a gas permeable membrane is placed a short distance from an end of an imaging window
Data Source
Figure 1
Figure 2~3
AI summary
A test cartridge (100) includes an input channel (110) to receive a liquid sample to be tested. A sample chamber (145) is coupled to the input channel to receive the sample. An air permeable membrane (150) is coupled between the sample chamber (145) and ambient (160) to prevent passage of the sample past the membrane (150) and stop movement of the sample in the sample chamber (145).