Cell Refractive Index Imaging for Apoptosis Viability Detection

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Solution Overview

Problem

Current methods for determining cellular viability in bioreactors, such as those used in pharmaceutical and medical fields, are limited in their ability to accurately differentiate between living and dead cells, particularly in distinguishing between necrosis and apoptosis, which affects production yield.

Innovation Solution

A method utilizing the refractive index of cells, specifically the real and imaginary parts of the refractive index, is employed to determine cellular states by analyzing images through phase microscopy, reconstructing complex light wave propagation, and applying a propagation operator to estimate refractive indices, enabling differentiation between living, dead, and apoptotic states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual counting methods are used to assess cell viability, then device complexity is reduced, but measurement precision and productivity deteriorate

Engineering Contradiction:
Improvecell viability assessment accuracyVSAvoidassay system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs colorimetric indicators that change color based on cell viability status. Live cells and dead cells exhibit distinct color characteristics that can be automatically detected by imaging systems, enabling precise quantitative assessment without complex manual procedures. The color change provides a direct visual and measurable signal of cell viability.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The invention replaces manual mechanical counting methods with automated optical imaging and image analysis systems. The automated system captures images of the assay wells and uses software algorithms to identify and count cells based on their color and morphological features, eliminating the need for manual microscopy and counting while significantly improving precision and throughput.

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

2Productivity

If manual counting methods are used to assess cell viability, then device complexity is reduced, but productivity deteriorates

Engineering Contradiction:
Improvecell viability assessment throughputVSAvoidassay system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention replaces manual mechanical counting methods with automated optical imaging and image analysis systems. The automated system captures images of the assay wells and uses software algorithms to identify and count cells based on their color and morphological features, eliminating the need for manual microscopy and counting while significantly improving precision and throughput.

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

Solution Approach 2:

The automated imaging system enables continuous assessment of multiple assay wells in sequence, allowing high-throughput evaluation of cell viability across numerous samples without interruption. The system can process multiple plates sequentially or in parallel, maintaining continuous productive operation rather than the stop-start nature of manual counting.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If automated cell counting devices are used, then measurement precision and productivity are improved, but device complexity and cost increase

Engineering Contradiction:
Improvecell viability assessment accuracyVSAvoidassay system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs colorimetric indicators that change color based on cell viability status. Live cells and dead cells exhibit distinct color characteristics that can be automatically detected by imaging systems, enabling precise quantitative assessment without complex manual procedures. The color change provides a direct visual and measurable signal of cell viability.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The invention replaces manual mechanical counting methods with automated optical imaging and image analysis systems. The automated system captures images of the assay wells and uses software algorithms to identify and count cells based on their color and morphological features, eliminating the need for manual microscopy and counting while significantly improving precision and throughput.

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

4Productivity

If traditional assays require multiple separate steps, then measurement precision may be maintained, but productivity and ease of operation deteriorate

Engineering Contradiction:
Improveassay throughputVSAvoidcell viability assessment accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The invention merges cell lysis, indicator release, and viability indication into a single integrated assay step. The lytic indicator is incorporated into the assay medium, so when cells are lysed (either naturally or induced), the indicator is released and immediately provides a colorimetric signal of viability. This eliminates separate lysis and measurement steps while maintaining accurate viability assessment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The assay system is designed to be universally applicable to different cell types and viability assessment needs. The same basic assay platform and imaging system can evaluate various cell lines, different viability conditions, and multiple parameters simultaneously, allowing one system to perform multiple functions without requiring separate specialized procedures for each application.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 method provides accurate differentiation between living, dead, and apoptotic cells, enhancing the detection of cellular states and improving production yield by identifying apoptotic cells before death occurs.

Implementation Method 1

the cells are lysed and the lytic indicator is released, thereby providing an indication that the cells are dead

Methodology Applied
Scientific EffectCell lysis:

Data Source

PatentEP4133251B1Method for determining the viability of cells
Publication Date: 2026.05.06 IPRASENSE SAS
  • EP4133251B1 patent drawingFigure 1
  • EP4133251B1 patent drawingFigure 2A~2B
  • EP4133251B1 patent drawingFigure 3A~3C

AI summary

A method for determining a state of a cell, the cell being placed in a sample, in contact with a culture medium, the method comprising: illuminating the sample with a light source and acquiring an image of the sample with an image sensor, the image sensor lying in a detection plane; from the acquired image, locating a position of the cell in a plane parallel to the detection plane; the method further comprising: from the acquired image, estimating a refractive index of the cell or a relative refractive index of the cell, the relative refractive index corresponding to a refractive index of the cell relative to the refractive index of the culture medium; from the estimation of the refractive index or of the relative refractive index, determining an index of interest of the cell; from the index of interest, classifying a state of the cell among predetermined states, the predetermined states comprising at least one apoptosis state and one living state.