Closed-Loop Fluorescence Cell Counting for Sterile Particle Identification

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Solution Overview

Problem

Existing cell counting methods face challenges in distinguishing cells from other particles, ensuring sterility, and automation suitability, particularly in open systems using bright-field microscopic observation.

Innovation Solution

A particle detection device with a closed system design, incorporating a holding part, flow channels, a mixing part with a solid-phase fluorescent reagent, an observation window, and a fluorescence detection part, along with valves and pumps for automated operation, enabling accurate cell counting through fluorescence detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If bright-field microscopic observation using white light is used for cell counting, then the method is simple and widely applicable, but it is difficult to distinguish cells from other particles in the suspension

Engineering Contradiction:
Improvesimplicity of cell counting methodVSAvoidaccuracy of cell identification
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses fluorescent reagents that cause cells to emit light at specific wavelengths when excited. Different cell types and states (live/dead) exhibit distinct fluorescence characteristics, enabling clear differentiation from non-fluorescent particles and accurate identification of cells in the suspension

Inventive Principle:
Principle #32Color changes

2Ease of operation

If manual sampling from parent suspension is performed in an open system, then the sampling process is simple and flexible, but sterility cannot be ensured

Engineering Contradiction:
Improveflexibility of sampling processVSAvoidsterility assurance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces manual mechanical sampling with an automated liquid feeding system that uses peristaltic pumps or syringe pumps to transfer suspension through closed tubing. This eliminates open manual operations while maintaining sampling flexibility and ensures sterility through the closed system design

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a closed tubing system and automated pumping mechanism as intermediaries between the parent suspension and the observation chamber. These intermediaries enable automated sampling while maintaining the closed sterile environment, eliminating the need for manual open sampling

Inventive Principle:
Principle #24Intermediary (Mediator)

3Extent of automation

If automated liquid feeding is implemented to transfer suspension, then automation suitability is improved, but the system complexity increases

Engineering Contradiction:
Improveautomation of cell countingVSAvoidcomplexity of automated system
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts the automated liquid feeding function into a modular cartridge that can be independently replaced. This separates the complex automated pumping and fluid handling mechanisms from the main instrument, making the overall system more manageable and easier to maintain while preserving full automation capability

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If fluorescent reagents are used for cell labeling, then cell identification capability is significantly improved, but reagent management and storage become more complex

Engineering Contradiction:
Improveparticle identification capabilityVSAvoidreagent management complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the fluorescent reagent storage, mixing, and delivery functions into an integrated cartridge system. The reagent is pre-loaded into the cartridge along with the necessary fluid handling components, eliminating the need for separate reagent storage, preparation, and management steps outside the cartridge

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs disposable cartridges that contain pre-loaded fluorescent reagents and single-use fluid handling components. After one use, the entire cartridge is discarded, eliminating the need for complex reagent management, sterilization, and maintenance of reusable components while maintaining high identification accuracy

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

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

Ensures sterility and automation suitability while accurately distinguishing cells from other particles, including live and dead cells, and simplifies reagent management through single-use cartridges.

Implementation Method 1

a fluorescence detection part that detects fluorescence emitted from the particles contained in the suspension through the observation window

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP4685454A1Particle detection device and particle detection method
Publication Date: 2026.01.28 FUJIFILM CORP
  • EP4685454A1 patent drawingFigure 1~2
  • EP4685454A1 patent drawingFigure 3
  • EP4685454A1 patent drawingFigure 4A~4C

AI summary

Provided are a particle detection device and a particle detection method that have high particle identification properties, can ensure sterility, and have automation suitability. A particle detection device includes a holding part that holds a suspension containing particles, a first flow channel that is connected to the holding part, an observation window that is connected to the first flow channel, a liquid feeding part that transfers the suspension held in the holding part to the observation window, and a fluorescence detection part that detects fluorescence emitted from the particles contained in the suspension through the observation window.