Retinal Tissue Culture Using Feeder-Free Stem Cell Aggregates

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Solution Overview

Problem

Existing methods for producing retinal cells or tissues from pluripotent stem cells require the use of feeder cells, which complicates the culturing process and stability, and there is a need for a more efficient method to maintain undifferentiated pluripotent stem cells without feeder cells.

Innovation Solution

Culturing pluripotent stem cells, particularly human iPS cells, in the absence of feeder cells and using a serum-free medium with a Sonic hedgehog signal transduction pathway activating substance to form spherical cell aggregates, which are then cultured in suspension to induce retinal cells or tissues with high efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feeder cells are used to maintain undifferentiated state of pluripotent stem cells, then the cells can be cultured successfully, but the culturing process becomes complicated and less stable

Engineering Contradiction:
Improvestability of undifferentiated state maintenanceVSAvoidcomplexity of culturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes feeder cells from the culturing system, replacing them with a defined culture medium containing specific growth factors (bFGF, TGF-β1, Nodal) that maintain the undifferentiated state of pluripotent stem cells. This eliminates the complexity and variability associated with feeder cells while maintaining culture stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical parameters of the culture system by defining specific growth factor concentrations and compositions in the culture medium. This replaces the biological complexity of feeder cells with controlled chemical parameters, achieving stable undifferentiated state maintenance through defined molecular signals.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional suspension culture methods are used without specific signaling pathway activators, then the process is simpler, but the formation of high-quality uniform cell aggregates is inefficient

Engineering Contradiction:
Improveuniformity and quality of cell aggregatesVSAvoidefficiency of retinal cell induction
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention applies Sonic hedgehog pathway activating substances during the suspension culture phase to pre-establish uniform cell aggregates with proper morphology and differentiation potential before initiating retinal cell differentiation. This preliminary action ensures high-quality aggregates that efficiently produce retinal cells, resolving the contradiction between aggregate quality and induction efficiency.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If pluripotent stem cells are cultured without feeder cells, then the process is simpler and more stable, but maintaining the undifferentiated state becomes difficult

Engineering Contradiction:
Improvesimplicity of culturing systemVSAvoidmaintenance of undifferentiated state
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention introduces specific growth factors (bFGF, TGF-β1, Nodal) as intermediary molecules that mediate the maintenance of undifferentiated state in the absence of feeder cells. These intermediaries replace the supportive function of feeder cells, enabling feeder-free culture while maintaining stem cell characteristics through defined molecular signals.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3868873B1Production method for retinal tissue
Publication Date: 2026.04.29 SUMITOMO PHARMA CO LTD
  • EP3868873B1 patent drawingFigure 1A~1D
  • EP3868873B1 patent drawingFigure 2A~2D
  • EP3868873B1 patent drawingFigure 3A~3D

AI summary

The present invention provides a method for producing retinal cells or a retinal tissue, comprising the following steps (1) - (3): (1) a first step of culturing human pluripotent stem cells in the absence of feeder cells and in a medium comprising a factor for maintaining undifferentiated state, (2) a second step of culturing the pluripotent stem cells obtained in the first step in suspension in the presence of a Sonic hedgehog signal transduction pathway activating substance to form a cell aggregate, and (3) a third step of culturing the aggregate obtained in the second step in suspension in the presence of a 1) a BMP signal transduction pathway activating substance to obtain an aggregate containing retinal cells or a retinal tissue.