Detachable Microfluidic Insert for Bubble-Free 3D Tissue Barriers
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Solution Overview
Problem
Existing microfluidic devices face challenges in forming accurate 3D tissue barriers due to drug or protein adsorption on PDMS surfaces, bubble formation during liquid injection, and difficulty in automating the injection process, which hinders their application in drug development and toxicity assessment.
Innovation Solution
A microfluidic device with a detachable insert and base, featuring a central channel, open chamber, and porous membrane, allows for the injection of cells and hydrogels without bubble formation, and enables automation through mechanical control, mimicking the structure and function of in vivo tissue barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDMS microchannels are used for cell culture, then 3D tissue barrier formation is enabled, but drug or protein adsorption occurs on the PDMS surface
Solution Approach 1:
The patent introduces a coating layer as an intermediary substance between the PDMS microchannel and the cells/drugs. This coating layer prevents direct contact between PDMS and the biological substances, thereby eliminating adsorption while maintaining the 3D tissue barrier structure. The coating acts as a mediator that preserves drug and protein availability for cellular interactions.
2Ease of operation
If liquid injection is performed through inlets into microchannels, then cell culture is enabled, but bubble formation occurs due to friction with the microchannel surface
Solution Approach 1:
The patent extracts or removes the problematic microchannel structure from the injection path. Instead of injecting through narrow microchannels that cause friction and bubbles, the design allows liquid injection into a larger open chamber where cells are deposited, eliminating the friction-induced bubble formation while still enabling cell culture in the microfluidic device.
3Reliability
If high-viscosity hydrogels are injected into microchannels through inlets, then 3D cell culture is enabled, but control of injection rate becomes difficult requiring greater expertise
Solution Approach 1:
The patent inverts the conventional injection approach. Instead of injecting hydrogels through narrow microchannels where viscosity control is difficult, the design enables injection into a larger open chamber with more favorable flow characteristics. This reversal of the injection geometry makes high-viscosity hydrogel injection much easier to control while still achieving 3D cell culture formation.
4Reliability
If multi-channel structures utilize surface tension to confine hydrogel to central channel, then 3D cell culture is enabled, but automation becomes difficult requiring careful manual control
Solution Approach 1:
The patent segments the injection process into distinct stages: first injecting cells into the open chamber, then separately injecting hydrogels. This segmentation of the injection process into discrete, controllable steps enables automation while maintaining proper hydrogel confinement. The open chamber geometry provides natural confinement that is easier to control automatically compared to surface tension-based confinement in narrow channels.
Data Source
AI summary
The present invention relates to a microfluidic device for mimicking the structure and function of an in vivo tissue barrier. Specifically, the present invention relates to a microfluidic device which replaces an animal model by mimicking the structure and function of a 2D-3D connective tissue barrier, a 3D tissue barrier, and a 3D-3D tissue barrier, and thus may be used as a model for new drug development and toxicity assessment, a method for culturing cells in the microfluidic device, and a method for mimicking an organ or a tissue using the microfluidic device.