Microfluidic Valve Unit for Continuous Cell Culture Flow
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Solution Overview
Problem
Conventional microfluid systems face limitations in continuous fluid conveyance due to limited liquid volumes and mechanical stress on cells caused by peristaltic pumps, which can lead to unspecific activation of immune cells during adhesion studies.
Innovation Solution
A valve unit with a bridge rectifier configuration and four stop valves allows continuous fluid flow in a predetermined direction between two fluid reservoirs and a flow chamber, enabling uninterrupted operation and reducing mechanical stress on cells by using a conveying means like a syringe pump or ferrofluid for pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If peristaltic pumps are used to convey fluid in closed circuits, then continuous flow is achieved, but intensive mechanical load is applied to suspended cells causing unspecific activation
Solution Approach 1:
The patent replaces the peristaltic pump's mechanical compression mechanism with a pressure-driven system using a reservoir and pressure differential. This substitution eliminates the intensive mechanical load on cells while maintaining continuous flow capability through pressure gradients rather than mechanical compression.
Solution Approach 2:
The invention extracts the fluid conveyance function from the peristaltic pump mechanism and separates it into a dedicated pressure generation system (reservoir with pressure differential) while removing the harmful mechanical interaction with cells. The pump mechanism is entirely removed from the fluid path.
2Duration of action of moving object
If open circuit systems with separate reservoirs are used, then fluid can be circulated, but the system complexity increases and continuous flow for prolonged periods is difficult to maintain
Solution Approach 1:
The patent merges the reservoir and flow chamber into a single integrated microfluidic device with internal fluid redistribution pathways. This combination eliminates the need for separate external reservoirs and complex circulation systems while enabling prolonged continuous flow through internal fluid recycling.
Solution Approach 2:
The invention implements continuous fluid circulation through integrated fluid redistribution channels that continuously redirect fluid from the flow chamber back to the reservoir. This creates an unbroken flow cycle that maintains continuous useful action without interruption or system reconfiguration.
3Volume of moving object
If small liquid volumes (1-500 ml) are used in reservoirs, then the system remains compact, but the flow duration is limited and requires frequent refilling
Solution Approach 1:
The patent implements continuous fluid circulation where the same small volume of liquid is repeatedly pumped through the flow chamber and redistributed back to the reservoir. This continuous recycling extends the effective flow duration indefinitely without requiring larger reservoir volumes or external fluid sources.
Solution Approach 2:
The integrated fluid redistribution system automatically recirculates fluid from the flow chamber back to the reservoir without external intervention. The system serves itself by continuously redistributing its own fluid volume, eliminating the need for manual refilling or external fluid supply.
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 solution enables continuous, uninterrupted fluid conveyance through microfluid systems, maintaining consistent flow direction and reducing mechanical stress on cells, thus preserving specific activation characteristics of immune cells during experiments.
Implementation Method 1
a conveying means, said first fluid reservoir being, via the flow chamber, in fluidic communication with the second fluid reservoir through the fluid channel array
Data Source
AI summary
The present invention relates to a valve unit for a microfluid system comprising a first and a second fluid reservoir, a flow chamber, a fluid channel array and a conveying means, said first fluid reservoir being, via the flow chamber, in fluidic communication with the second fluid reservoir through the fluid channel array,wherein the valve unit can be brought from a first state to a second state so that, in said first state, a fluid can be conveyed by the conveying means from said first fluid reservoir through the flow chamber in a predetermined direction of flow into the second fluid reservoir, and so that, in said second state, a fluid can be conveyed by the conveying means from said second fluid reservoir through the flow chamber in a predetermined direction of flow into the first fluid reservoir.