Microfluidic Valve for Liquid Plug Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In microfluidic systems, accurately positioning and maintaining a liquid volume during biochemical or chemical reactions is challenging due to pressure variations and evaporation, leading to increased complexity and cost in control technology and manufacturing, as well as reduced functional density and accuracy of test procedures.
Innovation Solution
A microfluidic structure with a first fluid line connected to a valve that allows selective connection or disconnection of its ends, creating a closed system to maintain constant pressure and prevent evaporation, using a shut-off position to ensure the liquid plug remains in place within a reaction chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex pressure regulation control technology is used to maintain liquid plug position, then positioning accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The system uses the reaction chamber itself as the containment structure for the liquid plug, eliminating the need for separate positioning devices. The chamber's geometry and the valve's shut-off position work together to automatically maintain liquid plug position without requiring complex external pressure regulation control systems.
Solution Approach 2:
The patent removes the complex pressure regulation control technology from the system while maintaining positioning accuracy through the simplified valve mechanism and reaction chamber design. The essential function of pressure control is extracted and replaced by the mechanical shut-off position of the valve.
2Measurement precision
If multiple valves are used for pressure control, then positioning accuracy is improved, but the space requirement and manufacturing cost increase
Solution Approach 1:
The patent combines the functions of multiple valves into a single valve with a shut-off position that can seal both ends of the first fluid line. This merging of functions reduces the number of separate valve components needed on the microfluidic chip, thereby reducing space requirements and manufacturing complexity.
Solution Approach 2:
The single valve is designed to perform multiple functions: it can connect or disconnect the first fluid line from the rest of the system, and it can also seal both ends of the fluid line to create a closed system. This multi-functionality eliminates the need for multiple specialized valves.
3Productivity
If heating is applied to accelerate reactions, then reaction speed is improved, but liquid evaporation and volume change occur
Solution Approach 1:
The valve's shut-off position creates a closed system in advance, sealing the liquid plug within the reaction chamber before heating begins. This pre-established seal prevents evaporation and volume loss during the heating process, cushioning against the harmful effects of thermal effects on the liquid.
4Ease of operation
If the first fluid line is continuously connected to the rest of the system, then ease of operation is improved, but liquid volume loss and positioning instability occur
Solution Approach 1:
The valve provides dynamic control over the connection state of the first fluid line. The system can switch between being connected to the rest of the microfluidic system and being sealed off. This dynamic capability allows the system to maintain reliability during reactions while preserving ease of operation for filling and emptying when needed.
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 simplifies the positioning and maintenance of the liquid plug, reduces the need for complex pressure regulation, prevents volume loss due to evaporation, and enhances the reliability and reproducibility of reactions by maintaining consistent pressure and preventing liquid loss.
Implementation Method 1
the same pressure acts everywhere within the closed fluid line, so that the same pressure acts on both sides of the liquid volume
Implementation Method 2
Heating can also lead to (partial) evaporation of the liquid and thus to an undesirable change in volume... No gases or vapors can escape from the closed system of the first fluid line
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a microfluidic structure for positioning a fluid volume having a plurality of fluid lines (10, 12, 14), of which the fluid volume is to be positioned in a first fluid line (10), and a valve (20). The first fluid line (10) has a first and a second end (16, 18), at which ends the first fluid line (10) is connected to said valve (20). The invention further relates to a method for positioning a fluid volume in a microfluidic system having a plurality of fluid lines (110, 132) and having a valve (122), wherein the first fluid line (110) comprises a first and a second end (118, 120), at which ends the first fluid line (110) is connected to said valve (122). The method comprises the following steps: connecting a second fluid line via a second passage in the valve to the first fluid line (110), filling the first fluid line (110) with a fluid volume, short-circuiting the first fluid line (110) by connecting the first and the second end (118, 120) via a first passage in the valve (122) or blocking the first fluid line (110) by closing the first and the second end (118, 120) by means of the valve (122).