Microfluidic Dosing Device With Meniscus Pinning Channel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microfluidic devices face challenges in achieving accurate and efficient liquid dosing at the microscale due to uncertainties in fluidic resistance and surface tension effects, which complicate precise control of fluid flow.
Innovation Solution
The device employs a continuous array of fixed-volume channel portions with hydrophilic internal surfaces, featuring shoulders that act as phase guides to pin the meniscus, allowing for precise control of liquid aspiration and dispension through capillary flow by varying the pressure applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure control is used for fluid dosing at the microscale, then fluid flow can be regulated through the channel, but uncertainties in fluidic resistance and surface tension effects reduce dosing precision
Solution Approach 1:
The invention changes the control parameter from pressure (continuous) to capillary pressure (discrete steps defined by channel geometry). By designing channels with specific cross-sectional area variations, the system creates discrete stable positions for the liquid meniscus, transforming the dosing control from pressure-dependent to geometry-dependent, thereby eliminating uncertainties from fluidic resistance and surface tension variations.
Solution Approach 2:
The invention replaces the mechanical pressure control system with a capillary action-based system. Instead of using pressure regulators and pumps to control fluid flow, the system uses the natural capillary forces arising from surface tension at the liquid-channel interface. The capillary pressure is determined by the channel geometry (cross-sectional area) rather than external mechanical pressure, providing more precise and repeatable dosing.
2Productivity
If continuous pressure control is applied for liquid aspiration and dispension, then fluid exchange can be achieved, but achieving sufficiently accurate dosage of volumes becomes difficult
Solution Approach 1:
The invention segments the continuous channel into sections with different cross-sectional areas, creating discrete stable positions for the liquid meniscus. Each segment corresponds to a specific volume, allowing the liquid to be aspirated or dispensed in precise discrete increments. The channel geometry is designed with alternating wider and narrower sections that define the stable meniscus positions, enabling accurate volume control through geometric segmentation rather than continuous pressure adjustment.
3Device complexity
If pressure control is used as the only measure for microscale fluid dosing, then the system remains simple, but dosing accuracy becomes insufficient for advanced applications
Solution Approach 1:
The invention enables the system to self-regulate liquid positioning through capillary forces without requiring external pressure control mechanisms. The channel geometry itself provides the control function, with the varying cross-sectional areas automatically creating stable meniscus positions. The liquid flow is self-regulated by the balance between capillary pressure and gravity, eliminating the need for complex pressure control systems while achieving high dosing accuracy.
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 configuration enables accurate dosing of liquids in discrete increments, improving the precision and efficiency of liquid handling at the microscale by leveraging meniscus pinning and burst pressure control.
Implementation Method 1
The channel is configured for capillary flow of the liquid portion therethrough
Implementation Method 2
a meniscus of the liquid portion at that end of the liquid portion thereby being pinned at the respective axial boundary
Implementation Method 3
the surface is preferably hydrophilic in order for the liquid to advance by capillary action whenever the contact angle with the surface is less than 90°
Data Source
AI summary
The invention provides devices and methods for dosing a liquid. A channel which ends in an opening of the device, for aspiration and/or dispension of a portion of the liquid through the opening and into the channel in an axial direction is configured for capillary flow of the liquid portion therethrough. The channel is formed along at least a part of its axial extension by a continuous array of, fixed-volume, advancement portions and pinning portions. At an axial boundary between each advancement portion and a respective pinning portion thereof which succeeds the advancement portion in the axial direction a phase guide is formed along an entire circumference of the channel, such that upon advancement of the liquid portion through the channel in the axial direction by capillary flow, a meniscus of the liquid portion at a downstream end of the liquid portion is pinned at the respective axial boundary.