Selective Cell Observation by Density Layer Separation

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Solution Overview

Problem

Existing cell observation methods struggle to accurately count cells in biological tissues containing fat due to difficulty in distinguishing between cells and lipid droplets, and centrifugation risks cell damage and loss.

Innovation Solution

An observation apparatus and method that separates a suspension into target and non-target layers based on specific gravity, using non-coaxial observation light and a filter to isolate and image target particles like cells, with a depth of field smaller than the target layer thickness, allowing clear imaging and counting without fat interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If centrifugation is used to separate cells and fat, then cell counting accuracy is improved, but cell damage and cell loss occur

Engineering Contradiction:
Improvecell counting accuracyVSAvoidcell integrity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts and removes the harmful factor (fat/lipid droplets) from the suspension using centrifugation before cell counting. By separating and discarding the fat layer, the observation is performed only on the cell-containing layer, thus improving counting accuracy without requiring harsh treatment of the cells.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent divides the suspension into distinct layers based on density: a fat layer (upper layer) and a cell layer (lower layer). This segmentation allows selective observation of the cell layer while excluding the fat layer, resolving the contradiction between accurate cell counting and cell integrity.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If bright field microscopy is used to observe cells, then observation simplicity is improved, but cell-fat distinction capability deteriorates

Engineering Contradiction:
Improveobservation simplicityVSAvoidcell-fat distinction capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent removes the fat component from the observation field by centrifugation, separating it from the cell layer. This extraction eliminates the source of confusion between cells and fat droplets, allowing simple bright field microscopy to achieve accurate cell counting without requiring complex imaging techniques.

Inventive Principle:
Principle #2Taking out (Extraction)

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 accurate cell counting by selectively observing cells while excluding fat, reducing the need for centrifugation and minimizing cell damage or loss, with enhanced imaging clarity and precision.

Implementation Method 1

a holding unit holding a suspension in a state of being separated into a target layer including target particles as an observation target among two or more kinds of particles included in the suspension and a non-target layer including particles other than the target particles among the two or more kinds of particles, the suspension including the two or more kinds of particles having different relative magnitudes of specific gravity with respect to a liquid

Methodology Applied
Scientific EffectSpecific gravity separation: Density Gradient

Implementation Method 2

an objective lens provided on the side of the target layer and magnifying an image of the target particles

Methodology Applied
Scientific EffectLight magnification: Lens

Implementation Method 3

The observation light source may output excitation light for exciting a fluorophore introduced into the target particles. The observation apparatus may have a filter that is provided between the objective lens and the imaging unit, blocks a wavelength component of the excitation light, and transmits a wavelength component of the fluorescence emitted from the target particles

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP4685461A1Observation apparatus and observation method
Publication Date: 2026.01.28 FUJIFILM CORP
  • EP4685461A1 patent drawingFigure 1~2
  • EP4685461A1 patent drawingFigure 3
  • EP4685461A1 patent drawingFigure 4

AI summary

Provided are an observation apparatus and an observation method capable of selectively observing target particles as an observation target among two or more kinds of particles included in a suspension. An observation apparatus includes: a holding unit that holds a suspension in a state of being separated into a target layer including target particles as an observation target among two or more kinds of particles included in the suspension and a non-target layer including particles other than the target particles among the two or more kinds of particles, the suspension including the two or more kinds of particles having different relative magnitudes of specific gravity with respect to a liquid; an observation light source that causes observation light to be incident from a side of the target layer; an objective lens that is provided on the side of the target layer and magnifies an image of the target particles; and an imaging unit that captures the image of the target particles magnified by the objective lens. A depth of field of an optical system including the objective lens is smaller than a thickness of the target layer.