Hanging Droplet Device for 3D Cell Structure Production

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Solution Overview

Problem

Current methods for producing 3D cell structures like spheroids, organoids, or embryonic bodies are costly, require specialized and expensive equipment, and are not suitable for high-throughput screening due to high reagent consumption and manual handling, limiting their application in drug testing and research.

Innovation Solution

A method involving a patterned substrate with hydrophilic and hydrophobic areas is used to form hanging aqueous microdroplets, allowing cells to agglomerate into 3D structures, which are then cultivated and screened using a device that enables high-density array formation without physical barriers, reducing costs and increasing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If specialized platforms with expensive equipment are used to produce 3D cell structures, then the quality and predictability of drug testing results is improved, but the production cost increases significantly

Engineering Contradiction:
Improvepredictability of drug testing resultsVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs disposable patterned substrates with hydrophilic/hydrophobic areas that can be mass-produced at low cost. These substrates form microdroplets containing 3D cell structures, eliminating the need for expensive specialized equipment while maintaining reliable drug testing results. The disposable nature ensures consistency and predictability without requiring costly infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention creates microdroplet copies of cell culture environments on patterned substrates. Each microdroplet serves as a miniaturized replica of a traditional cell culture well, allowing parallel processing of multiple samples. This copying approach enables high-throughput screening with simplified, cost-effective equipment while preserving the biological fidelity needed for predictable drug testing outcomes.

Inventive Principle:
Principle #26Copying

2Adaptability or versatility

If manual handling is used for cell seeding and medium exchange, then the process is flexible and adaptable, but the time consumption and labor requirements increase

Engineering Contradiction:
Improveflexibility of cell manipulationVSAvoidtime consumption for cell seeding and medium exchange
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the cell culture system into individual microdroplets on a patterned substrate, with each droplet containing a specific cell population or treatment condition. This segmentation allows parallel processing of multiple samples simultaneously. The hydrophilic/hydrophobic pattern enables automated liquid handling systems to efficiently seed and exchange media across numerous microdroplets in a single operation, dramatically reducing time while maintaining adaptability through the modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patterned substrate with pre-defined hydrophilic areas is prepared in advance, creating a ready-to-use template for cell seeding. This preliminary action establishes the spatial organization of cell cultures before actual experimentation begins. Automated systems can then efficiently follow the pre-established pattern for medium exchange and manipulation, reducing decision time and increasing throughput while maintaining flexibility for different experimental designs.

Inventive Principle:
Principle #10Preliminary action

3Volume of moving object

If high droplet volumes are used in hanging droplet methods, then the cell structures have adequate growth space, but the reagent consumption increases

Engineering Contradiction:
Improvedroplet volume for cell growthVSAvoidreagent consumption
Core Design Contradiction:
Volume of moving objectVSLoss of substance

Solution Approach 1:

The patent changes the volume parameter of droplets from the traditional large hanging droplets to small microdroplets (nanoliter to picoliter scale). The patterned substrate with controlled hydrophilic areas ensures that even at this reduced volume, cells have adequate space to form 3D structures. The hydrophobic barriers prevent droplet coalescence, maintaining volume stability. This parameter change dramatically reduces reagent consumption while preserving sufficient growth space through optimized microdroplet size and substrate geometry.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from three-dimensional hanging droplets suspended in air to two-dimensional microdroplets confined on a planar patterned substrate. This dimensional change allows precise control of droplet volume and position through the substrate pattern. The hydrophilic areas on the substrate define exact droplet boundaries, enabling minimal volume requirements to be met while preventing excessive reagent use. Cells still form 3D structures within these constrained 2D-defined microdroplets.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 cost-effective production and high-throughput screening of 3D cell structures, reducing reagent consumption and manual handling, while providing a more natural environment for cell growth and increased predictability in drug testing and research.

Implementation Method 1

forming an array of separated homogenous aqueous fluid microdroplets of a desired shape and size in a desired spatial pattern

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 2

providing a patterned substrate with a solid support coated with a layer or film comprising (i) hydrophilic areas having the desired shape and size; surrounded by (ii) hydrophobic areas separating the hydrophilic areas into the desired spatial pattern

Methodology Applied
Scientific EffectWettability: Wetting

Implementation Method 3

3D cell structures such as spheroids, organoids or embryonic bodies result from the agglomeration of adherent cells which assemble to three-dimensional cell structures based on cell-cell contacts

Methodology Applied
Scientific EffectCell-cell adhesion: Adhesive

Data Source

PatentEP3235899B1Method of producing 3D cell structures in hanging droplets and hanging droplet device comprising 3D cell structures
Publication Date: 2023.04.26 KARLSRUHER INST FUR TECH
  • EP3235899B1 patent drawingFigure 1a~1e
  • EP3235899B1 patent drawingFigure 2a~2c
  • EP3235899B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to a method of producing 3D cell structures, comprising the steps of forming an array of separated homogenous aqueous fluid microdroplets of a desired shape and size in a desired spatial pattern, wherein the separated homogenous aqueous fluid microdroplets comprise cells, wherein the forming of the array comprises providing a patterned substrate with a solid support coated with a layer or film comprising hydrophilic areas having the desired shape and size; surrounded by hydrophobic areas separating the hydrophilic areas into the desired spatial pattern; and applying the aqueous fluid comprising the cells to a multitude of the hydrophilic areas at the same time; turning the patterned substrate with the solid support upside down such that the separated homogeneous aqueous fluid microdroplets form hanging separated homogeneous aqueous fluid microdroplets; and agglomerating the cells comprised in the hanging separated homogeneous aqueous fluid microdroplets to 3D cell structures. Further, the present invention relates to a method for high-throughput screening of 3D cell structures, a hanging droplet device comprising hanging separated homogeneous aqueous fluid microdroplets which comprise 3D cell structures, and a use of the hanging droplet device for high-throughput screening and for cultivating 3D cell structures.