Sorting adherent cells via photoactivatable fluorescent labels

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Solution Overview

Problem

Existing methods for sorting biological cells, particularly adherent cells, are detrimental to cell health and alter cellular characteristics due to detachment from surfaces, and are prone to errors in identification and separation.

Innovation Solution

The method involves labeling adherent cells with photoactivatable fluorescent labels that change upon light exposure, allowing for identification and transformation of cells while still adherent, followed by detachment and sorting based on label differences in a non-adherent state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If adherent cells are detached from surfaces for sorting, then cell sorting can be performed, but cell health deteriorates and morphology alters

Engineering Contradiction:
Improvecell sorting capabilityVSAvoidcell health
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by labeling cells with photoactivatable fluorescent probes before detachment. The labeling step is performed while cells are still adherent and healthy, allowing the fluorescent marker to be properly attached and activated. This ensures that the sorting process can proceed after detachment without compromising cell health, as the critical identification step has already been completed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical detachment-based sorting with an optical detection system. By using photoactivatable fluorescent labels that can be activated by light exposure, the system substitutes mechanical manipulation (detachment) with optical detection and magnetic sorting. This allows cells to remain adherent during labeling and activation, preserving their health and morphology while enabling subsequent sorting based on fluorescent signal.

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

2Ease of operation

If adherent cells are detached for sorting, then cell separation can be achieved, but traceable markers on cell surfaces are obliterated

Engineering Contradiction:
Improvecell separation capabilityVSAvoidsurface markers
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent performs the labeling action before detachment, ensuring that fluorescent markers are attached to cell surfaces while cells are still adherent and their surface structures are intact. The photoactivatable fluorescent probes bind to specific cellular targets, and the activation step occurs before any mechanical disruption, preserving the association between the marker and the cell's surface characteristics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the state of the fluorescent label from non-fluorescent to fluorescent through photoactivation. This parameter change (fluorescence intensity) provides a detectable signal that correlates with the presence of target molecules on the cell surface, allowing identification and sorting without relying on physical surface features that might be lost during detachment.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If visual identification methods are used for adherent cells, then no detachment is needed, but identification is tedious and prone to error

Engineering Contradiction:
Improvecell integrityVSAvoididentification efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces manual visual identification with an automated optical detection system. Photoactivatable fluorescent probes provide specific molecular targeting, and upon light activation, emit fluorescent signals that can be detected by automated imaging or flow cytometry systems. This substitution eliminates the tedium and subjectivity of manual microscopy while maintaining cell integrity, as no detachment is required.

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

Solution Approach 2:

The patent utilizes color changes (fluorescence emission) as a detectable signal for cell identification. The photoactivatable fluorescent labels transition from non-fluorescent to fluorescent states, producing a distinct optical signal that can be automatically detected and quantified. This provides an objective, high-contrast marker that enables rapid and accurate identification compared to manual visual inspection.

Inventive Principle:
Principle #32Color changes

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 approach enables accurate and healthy sorting of adherent cells by maintaining cellular characteristics and reducing errors, allowing for precise differentiation and separation of subpopulations without detrimental detachment.

Implementation Method 1

labeling cells of said subpopulation and cells not of said subpopulation with a photoactivatable fluorescent label that is capable of undergoing a transformation upon exposure to light energy

Methodology Applied
Scientific EffectPhotoactivation: Photoluminescence

Data Source

PatentEP2643453B1Sorting of adherent cells by selective transformation of labels
Publication Date: 2017.08.30 BIO RAD LABORATORIES INC

AI summary

Adherent cells bearing characteristics that are detectable only in the adherent state can be sorted on the basis of these characteristics independently of their adherent state, by applying a transformable label to the entire population of cells, both those bearing the characteristics of interest and those not, in their adherent state and identifying the locations of the cells of interest on the adherent surface. The cells of interest, or all cells other than those of interest, are then selectively treated to transform the labels and achieve differentiation between the cells of interest and the remaining cells. All cells are then released from the adherent state and sorted in the same manner as non-adherent cells but on the basis of whether the labels are transformed or not transformed.