Nucleic Acid Isolation Using Polidocanol and Chaotropic Agents

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Solution Overview

Problem

Current methods for isolating nucleic acids from biological samples face challenges due to their low concentrations and presence in complex mixtures, with enzymes like desoxyribonucleases and ribonucleases degrading the target components during lysis, and interference from other substances like endotoxins, which complicates subsequent steps in diagnostics and bioanalytics.

Innovation Solution

A composition comprising a chaotropic agent, a buffering substance, a protease, and 0.5 to 4.9% (V/V) polidocanol or its derivative is used for lysis and enhancing the binding behavior of nucleic acids to silica surfaces, facilitating their detection and purification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lysis is performed to release cellular contents, then nucleic acids are freed for analysis, but degrading enzymes (desoxyribonucleases and ribonucleases) come into contact with and degrade the target nucleic acids

Engineering Contradiction:
Improvenucleic acid concentrationVSAvoidnucleic acid integrity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies this principle by using chaotropic agents to simultaneously achieve two goals: they denature the degrading enzymes (converting the harmful effect of enzyme presence) while also promoting nucleic acid binding to silica surfaces (creating a beneficial effect). The chaotropic conditions transform the harmful enzymatic environment into a controlled state where nucleic acids are protected and efficiently captured.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent uses chaotropic agents as intermediaries that mediate between the conflicting requirements of lysis and nucleic acid protection. These agents create a chemical environment that prevents enzyme-nucleic acid interaction while facilitating nucleic acid-silica binding, thus resolving the contradiction without requiring separate treatment steps.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If chaotropic agents and proteases are used to free and protect nucleic acids, then nucleic acid isolation is improved, but these substances interfere with reagents in subsequent diagnostic steps

Engineering Contradiction:
Improvenucleic acid isolation efficiencyVSAvoidinterference with subsequent reagents
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies this principle by extracting or removing the interfering chaotropic agents and proteases from the nucleic acid preparation through washing steps involving ethanol and buffer solutions. This separation allows the nucleic acids to be isolated in a clean state suitable for subsequent diagnostic applications without carryover interference.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent divides the isolation process into distinct segments: a lysis phase where chaotropic agents and proteases are used to release and protect nucleic acids, followed by a purification phase where these agents are removed. This segmentation allows each substance to perform its function optimally without causing interference in subsequent steps.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If nucleic acids are present in very small concentrations in complex mixtures, then detection sensitivity is challenged, but isolation and purification become more difficult

Engineering Contradiction:
Improvedetection sensitivityVSAvoidisolation process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies this principle by changing the chemical parameters of the isolation environment through chaotropic agents, which fundamentally alter the binding properties of nucleic acids to silica surfaces. This parameter change enables highly efficient capture of trace nucleic acids from complex mixtures, improving detection sensitivity while maintaining a relatively simple procedural framework.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a universal silica-based purification approach that works effectively across diverse sample types and nucleic acid concentrations. The same silica binding mechanism efficiently captures trace amounts of nucleic acids from complex biological mixtures, providing a multi-functional solution that addresses both low concentration detection and complex mixture purification.

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 approach effectively isolates and purifies nucleic acids by degrading interfering enzymes and enhancing binding to silica surfaces, improving the efficiency of nucleic acid detection and purification processes in diagnostics and bioanalytics.

Implementation Method 1

incubating the biological sample in the presence of a chaotropic agent

Methodology Applied
Scientific EffectChaotropic effect:

Implementation Method 2

a protease... degrading enzymes and enhancing binding to silica surfaces

Methodology Applied
Scientific EffectEnzymatic hydrolysis: Hydrolysis

Implementation Method 3

enhancing the binding behavior of nucleic acids to silica surfaces

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP1932913B1Nucleic acid isolation using polidocanol and derivatives
Publication Date: 2013.01.16 ROCHE DIAGNOSTICS GMBH
  • EP1932913B1 patent drawingFigure 1
  • EP1932913B1 patent drawingFigure 2
  • EP1932913B1 patent drawingFigure 3

AI summary

This invention relates to a composition comprising a chaotropic agent, a buffering substance, and 0.5 to 5 % (V/V) polidocanol or a derivative thereof. The invention is further related to uses of this composition and to a kit comprising the composition according to the invention. The invention is further related to a method for the detection of a nucleic acid in a biological sample comprising the steps of incubating the biological sample in the presence of a chaotropic agent, a buffering substance, and 0.5 to 5 % (V/V) polidocanol or a derivative thereof, optionally isolating the nucleic acid, optionally amplifying the nucleic acid, and detecting the nucleic acid. The invention is further related to a method for the purification of a nucleic acid in a biological sample comprising the steps of incubating the biological sample in the presence of a chaotropic agent, a buffering substance, and 0.5 to 5 % (V/V) polidocanol or a derivative thereof and isolating the nucleic acid thereby purifying the nucleic acid.