Variable-Volume Microfluidic Preparation for Repeatable Mixing
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Solution Overview
Problem
Existing microfluidic devices for preparing biological solutions face challenges in achieving high accuracy and repeatability while maintaining a compact size, and require complex air management to prevent liquid loss and bubble formation, leading to inefficiencies and increased maintenance costs.
Innovation Solution
A microfluidic device with a network of preparation chambers and a sampling zone, utilizing variable volume chambers and controlled fluid circulation to ensure precise volume measurement and mixing, eliminating the need for air purging and reducing bubble formation, and incorporating hyperelastic materials for deformable walls to enhance mixing and sample collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air propellant gas is used to move and mix liquids in the microfluidic circuit, then liquid movement and mixing are achieved, but air-biological liquid interface management becomes complex and liquid loss occurs
Solution Approach 1:
The patent removes the air propellant gas system entirely and replaces it with a closed liquid circulation system using a pump. This extracts the problematic air-liquid interface management from the system while maintaining the essential function of liquid movement and mixing through the microfluidic circuit.
Solution Approach 2:
The patent introduces a pump as an intermediary device to replace the air propellant gas. The pump directly moves liquids through the circuit without requiring air-liquid interfaces, serving as a mediator that eliminates the complexity of air interface management while achieving the same liquid transport function.
2Manufacturing precision
If two volumes of liquid are filled and moved through separate channels to a common coil for mixing, then dilution is achieved, but wetting and de-wetting problems cause liquid loss
Solution Approach 1:
The patent merges the two separate liquid channels into a single continuous circulation loop where both liquids are pumped simultaneously through the same microfluidic circuit. This eliminates the wetting and de-wetting cycles that occur when liquids are moved back and forth, preventing liquid loss while maintaining dilution accuracy.
Solution Approach 2:
The patent pre-fills the microfluidic circuit with the appropriate liquid volumes before mixing begins. The pump system is primed and the circuit is filled in advance, eliminating the need for repeated wetting and de-wetting operations that cause liquid loss during the mixing process.
3Reliability
If air purge is used to prevent liquid contamination in the circuit, then liquid purity is maintained, but air bubbles can appear in the mixture and distort measurements
Solution Approach 1:
The patent removes the air purge system entirely by using a closed liquid circulation system with a pump. Since liquids are moved continuously without air interfaces, there is no need for air purging, and consequently no air bubbles are introduced that could distort measurements.
Solution Approach 2:
The patent creates an inert liquid environment where all components of the microfluidic circuit are continuously filled with liquid, eliminating air pockets and bubbles. This liquid-filled environment prevents measurement distortion while maintaining liquid purity through the closed circulation system.
4Measurement precision
If large-size devices like haematology automatons are used to achieve high accuracy and repeatability, then measurement precision is improved, but device size increases and maintenance costs increase
Solution Approach 1:
The patent transitions from large-scale mechanical mixing and pumping systems to micro-scale fluidic operations. By miniaturizing the fluidic circuit and using micro-pumps, the device achieves the same measurement precision in a compact format, effectively moving the operation to a different size dimension.
Solution Approach 2:
The patent uses a simplified microfluidic model that replicates the essential functions of large haematology automatons. The microfluidic circuit copies the dilution and mixing functions in a miniaturized version, achieving comparable accuracy without the bulk and maintenance requirements of full-scale devices.
5Reliability
If professional maintenance intervention is required for microfluidic devices, then device reliability is maintained, but additional costs and periods of inactivity occur
Solution Approach 1:
The patent designs a microfluidic system with a closed liquid circulation architecture that is inherently resistant to contamination and malfunction. The pump-based system maintains continuous liquid flow without air interfaces, reducing the need for maintenance intervention and minimizing device downtime.
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
The device achieves high accuracy and repeatability in solution preparation with reduced size and complexity, minimizing fluid loss and maintenance needs, while allowing for flexible and adaptable solution preparation with precise volume control and efficient mixing.
Implementation Method 1
at least the first preparation chamber having a variable volume between a minimum volume V0 and at least one calibrated volume Vc
Implementation Method 2
incorporating hyperelastic materials for deformable walls to enhance mixing and sample collection
Implementation Method 3
The device also comprises means capable of controlling fluid circulation in the different parts of the circuit
Implementation Method 4
so that the fluid circulating from one preparation chamber to the other circulates in the sampling zone
Implementation Method 5
efficient mixing
Data Source
AI summary
A device for preparing a solution from a sample and a reagent, the device includes a microfluidic array having a sample supply inlet, a reagent supply inlet, a discharge outlet, a solution collection outlet, a sampling zone to which the inlets are connected, first and second preparation chambers connected to the sampling zone, arranged to either side of the sampling zone such that the liquid flowing from one preparation chamber to the other flows through the first sampling zone, the first preparation chamber having a volume that is variable between a minimum volume and a calibrated volume. The device includes valves interrupting the flow of the fluid at least at the two inlets and the collection and discharge outlets.