Microcapsule Fabrication via Segmented Microchannel Droplet Formation
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Solution Overview
Problem
Existing methods for fabricating alginic acid microcapsules result in non-uniform size distribution and decreased cell viability, with challenges in encapsulating a uniform number of cells and requiring expensive equipment for smaller diameters.
Innovation Solution
An apparatus and method utilizing spatially connected microchannels for cell distribution, droplet formation, and fluid exchange, including a cell supply unit, droplet forming unit, and fluid exchange unit, to create uniform microcapsules with improved cell viability by controlling fluid flux and exchanging dropletization inducing fluids with neutral fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If compressed air or electric field is used to form alginic acid microcapsules, then microcapsules can be formed, but the resultant capsules have large size distribution and require expensive apparatuses for diameters of 200 μm or smaller
Solution Approach 1:
The invention divides the microcapsule formation process into discrete stages using separate functional channels: a first channel for introducing alginic acid solution, a second channel for introducing dropletization inducing fluid, and a third channel for introducing droplet removal fluid. This segmentation allows precise control over droplet formation and removal, achieving uniform microcapsule sizes (particularly 200 μm or smaller) without requiring complex expensive apparatuses.
Solution Approach 2:
The invention introduces a dropletization inducing fluid as an intermediary substance that facilitates the formation of uniform droplets from the alginic acid solution. This intermediary fluid enables precise droplet size control and uniform microcapsule formation while simplifying the overall apparatus design compared to traditional compressed air or electric field methods.
2Manufacturing precision
If two-phase fluid chips are used to fabricate uniform microcapsules smaller than 200 μm, then uniform microcapsule size is achieved, but cell viability inside the microcapsule decreases after encapsulation
Solution Approach 1:
The invention extracts and removes the dropletization inducing fluid from inside the microcapsule through a dedicated third channel that introduces droplet removal fluid. This extraction step is crucial because it eliminates the harmful effects of the dropletization inducing fluid on cell viability while preserving the uniform microcapsule size achieved during formation. The droplet removal fluid facilitates the complete removal of the inducing fluid, ensuring high cell viability in the final microcapsule product.
Solution Approach 2:
The invention rapidly removes the dropletization inducing fluid from the microcapsule interior through the third channel after droplet formation is complete. This rapid removal minimizes the exposure time of cells to the inducing fluid, preventing viability loss while maintaining the benefits of uniform droplet formation. The quick transition from formation to removal ensures cell health is preserved.
3Productivity
If cells are encapsulated without distribution, then encapsulation process is simple, but uniform cell number cannot be achieved and clustered cells are not properly distributed
Solution Approach 1:
The invention performs preliminary cell distribution through the first channel before droplet formation occurs. The alginic acid solution containing cells is pre-mixed and distributed uniformly through the first channel, ensuring that cells are evenly dispersed throughout the solution. This preliminary action guarantees that when droplets are formed in subsequent steps, each droplet contains a uniform number of cells, achieving both high encapsulation efficiency and precise cell number uniformity.
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
Enables reproducible encapsulation of uniform cell numbers in microcapsules with improved cell viability and consistent size, overcoming the limitations of previous methods by ensuring uniform microcapsule formation and enhanced cell survival.
Implementation Method 1
a droplet forming unit in which a dropletization inducing fluid supplied from one of the plurality of microchannels joins with the fluid mixture of the cells and the cell dropletizing material to form a droplet
Implementation Method 2
a main channel in which the droplet is solidified by the dropletization inducing fluid to form a microcapsule and the microcapsule is transferred
Data Source
AI summary
The present invention relates to an apparatus and a method for fabricating a microcapsule, more particularly to an apparatus and a method for fabricating a microcapsule, which enable to encapsulate uniform cell number in a microcapsule through cell distribution, improve cell viability in the microcapsule through fluid exchange, and ensure uniform microcapsule size. The apparatus for fabricating a microcapsule according to the present invention uses a plurality of microchannels which are spatially connected with one another and are designed such that fluid flows through them in a particular direction, and comprises a cell supply unit which supplies a fluid mixture of cells and a cell dropletizing material; and a droplet forming unit in which a dropletization inducing fluid supplied from one of the plurality of microchannels joins with the fluid mixture of the cells and the cell dropletizing material to form a droplet.