Microfluidic System for Capsule Transfer and Gelation
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Solution Overview
Problem
Current microfluidic systems face challenges in efficiently transferring and gelating polymeric capsules containing biological elements, such as cells, due to deformation and lack of homogeneity, especially when crossing liquid phases, which affects the preservation of the capsules' spherical shape and cell viability.
Innovation Solution
A microfluidic system with a network of microchannels and transfer means, including pads and interface stabilization pillars, facilitates the transfer of elements from one liquid phase to another by forced convection, ensuring minimal deformation and maintaining the spherical shape of capsules through controlled deflection and stabilization, allowing for gelation in a neutral pH environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive transfer principle (deflector) is used to transfer particles between liquid phases, then particle transfer is achieved without high-intensity forces, but transfer efficiency is low and requires complex device structures
Solution Approach 1:
The patent replaces passive mechanical deflectors with an active acoustic field (ultrasonic waves) to transfer capsules between liquid phases. The acoustic radiation force enables controlled capsule migration across the interface without mechanical contact, maintaining capsule integrity while significantly improving transfer efficiency and eliminating the need for complex deflector structures.
Solution Approach 2:
The patent utilizes changes in acoustic field parameters (frequency, intensity, positioning) to control capsule transfer. By adjusting these parameters, the system can selectively transfer capsules of different sizes and properties, enabling efficient separation and transfer while maintaining capsule integrity through non-contact acoustic forces.
2Productivity
If brutal transfer with high-intensity forces is used to transfer capsules between phases, then transfer speed is fast, but capsule deformation is significant and cell viability decreases
Solution Approach 1:
The patent replaces high-intensity mechanical forces with acoustic radiation forces for capsule transfer. The ultrasonic acoustic field exerts gentle, distributed forces on capsules, enabling rapid transfer between liquid phases without the mechanical stress and deformation associated with traditional brute-force methods, thereby preserving cell viability.
Solution Approach 2:
The patent introduces an acoustic field as an intermediary between the capsule and the liquid phase interface. This acoustic mediator enables capsule transfer through radiation pressure without direct mechanical contact or high-intensity mechanical forces, achieving fast transfer while maintaining capsule integrity and cell viability.
3Manufacturing precision
If manual external gelation process is used for capsule gelation, then gelation can be achieved, but process automation is low and homogeneity is poor
Solution Approach 1:
The patent integrates gelation directly into the microfluidic chip, enabling continuous gelation of capsules as they flow through the device. The crosslinking reagents are continuously supplied through integrated channels, and capsules are gelated in-situ without manual intervention, achieving both high automation and homogeneous gelation throughout the capsule population.
Solution Approach 2:
The patent merges the gelation process with the capsule transfer and separation processes within a single integrated microfluidic device. The gelation reagents are delivered through the same chip channels, and gelation occurs in-situ during capsule flow, combining multiple operations into one continuous automated process that ensures uniform gelation.
4Manufacturing precision
If external gelation in polycation bath is used, then capsule gelation is achieved, but capsule spherical shape is deformed and polydispersity increases
Solution Approach 1:
The patent uses an integrated microfluidic channel system as an intermediary to deliver gelation reagents directly to capsules in a controlled manner. This eliminates the need for external polycation baths that cause deformation, as the reagents are delivered through confined channels that maintain capsule spherical shape while enabling uniform crosslinking.
Solution Approach 2:
The patent implements localized gelation within specific regions of the microfluidic chip. Gelation reagents are delivered to specific zones where capsules flow, enabling controlled, uniform gelation in a localized environment that preserves capsule shape, rather than exposing all capsules to external polycation baths that cause deformation and polydispersity.
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 enables efficient, homogeneous, and biocompatible transfer and gelation of capsules, maintaining cell viability and achieving precise size adaptation, reducing the need for high-intensity forces and manual processes, thus improving the encapsulation and transplantation of cells.
Implementation Method 1
A microfluidic system with a network of microchannels and transfer means, including pads and interface stabilization pillars, facilitates the transfer of elements from one liquid phase to another by forced convection
Implementation Method 2
Especially in the case of a two-phase system, this force must be sufficient to force the particles across the interface between the two liquids. However, this passage is impeded by the surface tension between the two liquids and by capillary forces.
Implementation Method 3
The pillar array technique was developed for sorting by Deterministic Lateral Displacement (DLD). This technique relies on the use of a periodic array of obstacles that either perturb or not the trajectory of the particles to be sorted.
Data Source
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Figure 8a~19a
AI summary
The invention relates to a microfluidic system including a unit for extracting elements from one liquid phase to at least one other liquid phase, a use of said system for performing said extraction, preferably for gelling polymer capsules coating such elements by cross-linking, and a method for extracting said elements. Said system comprises a substrate in which a network of micro-channels is etched, including a unit (10) for extracting elements (E), including: a depleting micro-channel (11) which carries a first phase (A) to be depleted; at least one enriching channel (12) which carries a second phase (B) to be enriched, said micro-channels meeting at two junctions upstream (Ja) and downstream (Jb) and forming a transfer chamber (13) between said junctions, each junction being such that the micro-channels are axially parallel or form an acute angle on either side of the junction; and a transfer means (14) arranged in the depleting micro-channel for diverting the elements towards the enriching micro-channel. According to the invention, the transfer means includes blocks (14) extending transversely to the axis of the depleting micro-channel, and the extraction unit includes an interface stabilising means (16) arranged downstream from the transfer means between the junctions and including pillars (16) or a surface coating located on an area of the downstream junction facing at least one of the micro-channels.