Acidic Detergent Lysis for DNA Quantification

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Solution Overview

Problem

Current methods for determining DNA or RNA content in cells are complex, time-consuming, and often result in cell loss and aggregation, making it difficult to accurately quantify nucleic acid in adherent cell lines and promoting noise in analysis.

Innovation Solution

A two-step method involving the use of a weakly acidic solution with a non-ionic detergent and a DNA-specific dye like DAPI to release and label cell nuclei, followed by neutralization, allowing for direct fluorescence quantification without fixation, which reduces aggregation and noise, and can be performed at low magnification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional DNA staining methods are used with non-ionic detergents or alcohol fixation, then cells can be permeabilized for staining, but the methods require cells to be in suspension, require washing steps with centrifugation that results in cell loss, and promote cell aggregation

Engineering Contradiction:
ImproveDNA content quantification accuracyVSAvoidcell loss
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The invention changes the chemical parameters of the lysis solution by using a weakly acidic solution (pH 2.0-3.0) containing a non-ionic detergent instead of conventional neutral pH buffers or alcohol fixation methods. This parameter change enables direct lysis of adherent cells without requiring detachment or washing steps, thereby preventing cell loss while maintaining effective DNA staining capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts the cell lysis function into a single weakly acidic detergent solution that simultaneously performs lysis, permeabilization, and prevents aggregation. This eliminates the need for separate detachment, washing, and resuspension steps that conventionally cause cell loss

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If conventional DNA staining methods are used with non-ionic detergents or alcohol fixation, then cells can be permeabilized for staining, but washing steps and centrifugation are required which result in cell loss

Engineering Contradiction:
ImproveDNA content quantification accuracyVSAvoidanalysis time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention merges multiple functions (cell lysis, membrane permeabilization, and aggregation prevention) into a single weakly acidic detergent solution treatment step. This consolidation eliminates the need for separate washing and centrifugation steps, significantly reducing analysis time while maintaining DNA staining quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention enables continuous processing by using a weakly acidic solution that maintains cells in a stable, non-aggregated state throughout the staining process without requiring interruption for washing or centrifugation, thereby reducing total analysis time

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If conventional DNA staining methods are used with non-ionic detergents or alcohol fixation, then cells can be permeabilized for staining, but they promote cell aggregation which hampers DNA content quantification of individual cells

Engineering Contradiction:
ImproveDNA content quantification accuracyVSAvoidsample preparation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the pH parameter to weakly acidic (pH 2.0-3.0) and uses a non-ionic detergent to create a solution environment that prevents cell aggregation during lysis. This parameter change simplifies sample preparation by eliminating the need for additional dispersing steps while maintaining individual cell integrity for accurate DNA quantification

Inventive Principle:
Principle #35Parameter changes

4Productivity

If acid lysis is performed to release nuclei from cells, then nuclei can be released efficiently, but the sample remains acidic which may interfere with subsequent nucleic acid labeling and analysis

Engineering Contradiction:
Improvenuclei release efficiencyVSAvoidnucleic acid labeling accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention performs preliminary neutralization of the acidic lysis solution immediately after nuclei release. This preliminary action prepares the sample for subsequent nucleic acid labeling by adjusting the pH to a neutral range, ensuring optimal conditions for fluorescent dye binding while maintaining the benefits of efficient acid lysis

Inventive Principle:
Principle #10Preliminary action

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 a simple, rapid, and reliable means to quantify nucleic acid content with reduced variability and noise, enabling accurate cell cycle analysis and other cellular assessments without the need for cell detachment or centrifugation.

Implementation Method 1

Adding an acidic agent comprising a detergent causing lysis to the sample causing acidification of the sample to a pH level between 2.0 and 3.0

Methodology Applied
Scientific EffectLysis:

Implementation Method 2

Adding a fluorescent labelling agent to the sample, wherein the fluorescent labelling agent interacts with nucleic acid

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

Adding a neutralizing agent for neutralising the sample after or simultaneous to adding the labelling agent

Methodology Applied
Scientific EffectNeutralization:

Data Source

PatentEP2534463B1Method for analysis of cellular DNA content
Publication Date: 2020.01.08 CHEMOMETEC AS
  • EP2534463B1 patent drawingFigure 1
  • EP2534463B1 patent drawingFigure 2~3
  • EP2534463B1 patent drawingFigure 4~5

AI summary

Disclosed is a fast and simple method for quantification of nucleic acid of biological cells as 2 -step protocol. In the first step cells are treated with an acidic solution containing a non- ionic detergent and a fluorescent DNA specific label. In the second step the sample may be neutralised. Determining of the content of nucleic can be performed by fluorescence microscopy. The method may also be used for obtaining information of cell cycle analysis, ploidy determination, measurements of nucleotide incorporation and assays for proliferation, health, stress level, apoptosis, necrosis, or other state of conditions of cells. The invention also relates to a kit of parts comprising an acidic agent, a detergent, a labelling agent and optionally a neutralization agent.