Microfluidic Device Aliquoting via Sealing Liquid Meniscus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microfluidic aliquoting methods for lab-on-a-chip systems face challenges such as manual pipetting steps, centrifugation requirements, and difficulties in achieving complete filling of cavities due to capillary pressure and air trapping, especially with hydrophobic surfaces and polymers lacking gas permeability or elasticity.
Innovation Solution
A method and device utilizing a sealing liquid with different wetting characteristics to achieve complete and reliable filling of microfluidic cavities through geometric design, eliminating the need for evacuating, gas-permeable substrates, or centrifugation, and enabling fully automated operation, with optional degassing and reagent pre-storage to prevent entrainment and bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centrifugation is used to remove air trapped in cavities, then air removal is achieved, but device complexity and operational requirements increase significantly
Solution Approach 1:
The patent extracts the air removal function from complex mechanical systems (centrifugation) and achieves it through a simple geometric design feature - the overflow outlet positioned at a specific height that allows air to be expelled naturally during the filling process, eliminating the need for external centrifugation equipment
Solution Approach 2:
The microfluidic device performs air removal autonomously through its own geometric design. The overflow outlet and cavity geometry work together to automatically expel trapped air during liquid filling without requiring external assistance from centrifugation systems or other complex mechanisms
2Manufacturing precision
If complete filling of hydrophobic cavities is achieved through external pressure, then filling completeness improves, but risk of air trapping increases
Solution Approach 1:
The patent applies preliminary action by designing the overflow outlet position and cavity geometry in advance to guide the liquid filling process. The geometric features pre-establish the flow path that prevents air trapping before the filling operation begins, rather than attempting to correct air trapping issues during or after filling
Solution Approach 2:
The overflow outlet acts as an intermediary element that mediates between the incoming liquid and the trapped air. It provides a controlled escape path for air bubbles while allowing liquid to fill the cavity completely, resolving the conflict between filling completeness and air removal
3Adaptability or versatility
If manual pipetting steps are used for aliquoting, then flexibility is maintained, but automation capability is reduced
Solution Approach 1:
The microfluidic device performs aliquoting autonomously through its geometric design. The cavity array and overflow outlet configuration automatically portion the liquid into equal volumes as the liquid fills and overflows, eliminating the need for manual pipetting while maintaining precise volume control
Solution Approach 2:
The patent replaces the manual mechanical pipetting system with a passive geometric aliquoting mechanism. The cavity geometry and overflow design substitute for the mechanical pipette, achieving automated portioning through fluid dynamics and geometric constraints rather than manual mechanical operation
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
Ensures complete, thermally stable, and fully automated aliquoting of sample liquids with reduced bubble formation and entrainment, allowing for efficient microfluidic functionality and high multiplexed analysis capabilities without manual intervention.
Implementation Method 1
the capillary forces present therefore counter complete filling of the microfluidic structure and correspond to a capillary pressure that prevents spontaneous advancing of the fluid meniscus
Implementation Method 2
wherein the sample liquid and the sealing liquid have different wetting characteristics
Data Source
AI summary
A method for aliquoting a sample liquid using a sealing liquid in a microfluidic device includes combining the sample liquid and the sealing liquid, which have different wetting behaviors, to form a two-phase system separated by a boundary surface. The microfluidic device includes a chamber with at least one inlet channel for introducing the liquids and a plurality of cavities configured to be filled via the inlet channel. The inlet channel and the cavities have a geometry that is defined in dependence on the respective wetting behaviors of the sample liquid and the sealing liquid. The method first includes introducing the sample liquid to form a first meniscus configured by the defined geometry, e.g. concave, to fill the cavities. The method further includes introducing the sealing liquid to form a second meniscus configured by the existing, greater contact angle and the defined geometry, e.g. convex, to cover the filled cavities.