Nervous System Cell Spheroid with 15–30% Outer Layer for Drug Response

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Solution Overview

Problem

Existing nervous system cell-containing spheroids exhibit low drug responsiveness, particularly in 3D culture, compared to 2D culture, limiting their effectiveness in drug screening and evaluation.

Innovation Solution

A nervous system cell-containing spheroid is developed with a specific proportion of the volume of one cell layer at the outer edge to the entire spheroid ranging from 15% to 30%, optimizing the cell density and composition to enhance drug responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If 3D culture is used for nervous system cell-containing spheroid, then cell complexity and physiological relevance are improved, but drug responsiveness deteriorates

Engineering Contradiction:
Improvephysiological relevanceVSAvoiddrug responsiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a specific structural configuration within the spheroid where a single cell layer is positioned at the outer edge with a controlled volume proportion (15-30%). This localized structural feature ensures that drug molecules can effectively reach the nerve cells through the outer cell layer, maintaining high drug responsiveness while preserving the physiological relevance of 3D culture. The specific arrangement of cells at different locations within the spheroid resolves the contradiction between 3D complexity and drug accessibility.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If cell density in spheroid is increased, then physiological function is improved, but drug penetration and responsiveness deteriorate

Engineering Contradiction:
Improvecell densityVSAvoiddrug responsiveness
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the spheroid into distinct functional zones: an outer cell layer with specific volume proportion (15-30%) that serves as the primary interface for drug penetration, and an inner core region with higher cell density that maintains physiological functions. This segmentation allows the outer layer to facilitate drug access while the inner dense region preserves physiological relevance, resolving the contradiction between cell density and drug responsiveness.

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If spheroid size is increased, then more cells are available for testing, but drug penetration time and responsiveness deteriorate

Engineering Contradiction:
Improvenumber of cellsVSAvoiddrug penetration time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies parameter changes by precisely controlling the volume proportion of the outer cell layer (15-30%) rather than simply increasing or decreasing overall spheroid size. This parameter optimization ensures that even as the spheroid grows to accommodate more cells for statistical significance, the outer layer maintains an optimal thickness for rapid drug penetration, thus increasing cell number without proportionally increasing drug penetration time.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4613846A1Nervous system cell-containing spheroid, method for producing nervous system cell-containing spheroid, and method for evaluating test substance
Publication Date: 2025.09.10 RICOH CO LTD
  • EP4613846A1 patent drawingFigure 1~2
  • EP4613846A1 patent drawingFigure 3
  • EP4613846A1 patent drawingFigure 4~5

AI summary

What is provided is a nervous system cell-containing spheroid having suitable drug responsiveness. There are provided a nervous system cell-containing spheroid including at least one kind of nerve cells and nervous system cells other than the nerve cells, in which the proportion of the volume of one cell layer positioned at an outer edge of the spheroid to the volume of the entire spheroid is 15% to 30%; a method for producing the nervous system cell-containing spheroid; and a method for evaluating a test substance, the method including a step of incubating a nervous system cell-containing spheroid in the presence of a test substance, and a step of evaluating an effect of the test substance on the nervous system cell-containing spheroid, in which the nervous system cell-containing spheroid includes at least one kind of nerve cells and nervous system cells other than the nerve cells, and the proportion of the volume of one cell layer positioned at an outer edge of the spheroid to the volume of the entire spheroid is 15% to 30%.