Microfluidic Reagent Structures for Homogeneous Dissolution
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Solution Overview
Problem
In capillary driven microfluidic systems, achieving homogeneous dissolution of reagents is challenging due to fast dissolution rates leading to reagent accumulation and long diffusion times for large molecules, which hinder fast sample-to-answer processes.
Innovation Solution
A capillary driven microfluidic system arrangement featuring a channel with a valve and structures for holding dried reagents, where the structures are wider than the channel, allowing fluid to enter, dissolve the reagents, and diffuse back, with an actuator controlling the valve to open after a predetermined time for homogeneous dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If reagents are stored dried on chip and dissolved by buffer or sample fluids, then shelf time of the device is extended, but reagent accumulation occurs at the front of the filling liquid resulting in non-homogeneous dissolution
Solution Approach 1:
The channel is divided into multiple segments or zones along its length. Reagent structures are distributed at different positions rather than concentrated at one location. This segmentation prevents reagent accumulation at a single point and promotes more uniform dissolution throughout the channel, while still allowing the device to maintain extended shelf life through dried reagent storage.
2Stability of the object's composition
If active fluidics elements such as a mixer are used to distribute reagents, then homogeneous dissolution is achieved, but device complexity and fabrication difficulty increase
Solution Approach 1:
The complex active mixing elements are extracted or removed from the system. Instead of using mixers or other active fluidics components, the invention achieves homogeneous dissolution through passive distribution of reagent structures along the channel. This simplifies the device architecture while maintaining effective reagent mixing through the natural flow and dissolution process.
3Device complexity
If molecule diffusion is used for reagent distribution in a simpler fluidic structure, then device complexity is reduced, but diffusion time exceeds 10 minutes for large molecules which is not desirable for fast sample-to-answer time
Solution Approach 1:
Reagents are pre-distributed along the channel in the form of dried structures before the actual dissolution process begins. When buffer or sample fluid flows through the channel, it encounters reagent structures at multiple positions simultaneously, enabling parallel dissolution and distribution. This preliminary spatial arrangement dramatically reduces the time required for homogeneous dissolution compared to relying solely on diffusion from a single point, while maintaining simple fluidic structures.
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 arrangement prevents reagent accumulation, reduces diffusion time by controlling fluid flow and reagent distribution, ensuring homogeneous dissolution independent of channel length, and is suitable for various molecule sizes and types.
Implementation Method 1
capillary driven microfluidic system
Implementation Method 2
molecule diffusion
Data Source
AI summary
There is provided an arrangement in a capillary driven microfluidic system for dissolving a reagent in a fluid. The arrangement (200) comprises a channel (102) for receiving a fluid at a first end, a valve (105) arranged at a second end of the channel so as to control a flow of the fluid to stop as it reaches the second end of the channel, and an actuator (108) for opening the valve (105) a predetermined time after receipt of the fluid by the channel (102). The arrangement further comprises one or more structures (106) for holding a dried reagent. The one or more structures (106) each has a width (W2) which is larger than a width (W1) of the channel (102), and the one or more structures are coupled to a side wall of the channel such that the fluid is allowed to enter the one or more structures from the channel, dissolve the dried reagent held therein, and diffuse back into the channel.