Microfluidic Flow Cell with Integrated Dry Reagent in Open Channel End
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Solution Overview
Problem
The integration of dry reagents into microfluidic elements is challenging due to damage from manufacturing processes like adhesive bonding and welding, and handling small carrier elements is difficult, especially when multiple reagents are required for different reactions.
Innovation Solution
The dry reagent is arranged in an outwardly open end portion of the channel region, allowing for introduction without damage during manufacturing, with a separate end portion for liquid introduction that is in fluid communication, enabling redissolution through pneumatic pressure and diffusion, and the use of hydrophilic surfaces and capillary channels for efficient liquid handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dry reagents are integrated into microfluidic elements using conventional methods (carrier elements), then reagents can be incorporated, but the reagents are damaged by subsequent welding and adhesive bonding processes
Solution Approach 1:
The microfluidic element is divided into distinct regions: a channel region for liquid transport and a separate reaction region containing the dry reagent. This segmentation allows the reagent to be isolated from manufacturing processes that would damage it, while still enabling its functional integration into the microfluidic system.
Solution Approach 2:
A permeable membrane or porous barrier is introduced as an intermediary between the channel region and the reagent region. This intermediary allows controlled interaction between liquid and reagent while protecting the reagent from direct exposure to manufacturing processes such as welding and adhesive bonding.
2Adaptability or versatility
If small carrier elements with diameters of 1 mm are used to hold dry reagents, then reagents can be positioned, but handling becomes very difficult especially when multiple reagents are required
Solution Approach 1:
Multiple carrier elements holding different dry reagents are merged into a single integrated structure within the microfluidic element. This combining approach maintains the ability to handle multiple different reagents while providing a unified, easier-to-manage structure that can be processed as one component.
Solution Approach 2:
The reagent positioning approach transitions from using small three-dimensional carrier elements to a two-dimensional planar arrangement within the microfluidic channel region. This dimensional change allows multiple reagents to be positioned in a flat, accessible layout that is easier to handle and load, especially when multiple different reagents are involved.
3Ease of manufacture
If the channel region has an outwardly open end portion for dry reagent introduction, then reagents can be introduced without damage, but liquid introduction requires a separate access point
Solution Approach 1:
The outwardly open end portion of the channel region serves dual functions: it provides access for introducing dry reagents during manufacturing and also serves as an access point for introducing liquid samples during operation. This multi-functionality eliminates the need for separate access openings, simplifying the overall device configuration while maintaining ease of manufacture.
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 approach reduces production outlay, protects reagents during manufacturing, and facilitates efficient mixing and analysis by allowing controlled redissolution and thorough mixing of reagents with liquid samples, while minimizing evaporation and ensuring precise control over fluid movement.
Implementation Method 1
the end portion and the further end portion are each configured as a capillary channel and, in particular, are hydrophilized
Implementation Method 2
The end portion that has the dry reagent and the further end portion for introducing the quantity of liquid are expediently each bounded by a constriction of the channel cross section. The constriction forms a barrier for liquid up to a limit pressure, but is permeable for air.
Implementation Method 3
By an operating device, to which the microfluidic element can be coupled in a hermetically leaktight fashion, the quantity of fluid can be transferred by means of an applied pneumatic pressure into the end portion that has the dry reagent
Implementation Method 4
where redissolving of the dry reagent takes place, for example by diffusion or moving the quantity of fluid to and fro
Data Source
AI summary
A microfluidic element, in particular a flow cell, for processing a quantity of liquid which is to be transported in a channel region of the microfluidic element and which comes into contact with a dry reagent integrated in the microfluidic element. The dry reagent is located in an outwardly open end portion of the channel region. A method for manufacturing such a microfluidic element, a combination of the microelement and an operator device, and a method for operating the microelement using the operator device.