Biscationic Organic Compounds for Nucleic Acid Adsorption Under Low-Salt Conditions

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Solution Overview

Problem

Current nucleic acid purification methods require high concentrations of chaotropic substances and alcohols, which are costly, hazardous, and complicate the adsorption process, especially when dealing with complex sample materials, and often necessitate high salt concentrations and specific safety precautions.

Innovation Solution

The use of biscationic organic compounds, such as bis-benzimidazolium, bis-imidazolium, and bis-guanidinium cations, in aqueous compositions with buffer salts at lower salt concentrations (between 5 mM and 300 mM) to facilitate the adsorption of nucleic acids to solid phases like silica without the need for chaotropic substances or high alcohol concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high concentrations of chaotropic substances (1 M to 6 M) are used for adsorption of nucleic acids to solid phase, then adsorption efficiency is improved, but the complexity of composition and cost increase

Engineering Contradiction:
Improveadsorption efficiencyVSAvoidcomposition complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the concentration parameter of chaotropic substances from high (1-6 M) to low (5-300 mM) by introducing biscationic organic compounds as alternative adsorption promoters, thereby simplifying the composition while maintaining adsorption efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the need for high concentrations of chaotropic substances and complex additives by using biscationic organic compounds, which achieve the same adsorption promotion effect with simpler, lower-concentration formulations

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If high concentrations of chaotropic substances are used to inhibit nucleases, then nucleic acid stability is improved, but the cost and complexity of the procedure increase

Engineering Contradiction:
Improvenucleic acid stabilityVSAvoidprocedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the concentration parameter from high to low by using biscationic organic compounds that effectively inhibit nucleases at much lower concentrations than traditional chaotropic substances, thereby reducing procedure complexity while maintaining nucleic acid stability

Inventive Principle:
Principle #35Parameter changes

3Productivity

If alcohols are used for adsorption enhancement, then adsorption efficiency is improved, but safety hazards and handling difficulties increase

Engineering Contradiction:
Improveadsorption efficiencyVSAvoidsafety hazards
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces flammable, hazardous alcohols with safer, non-flammable biscationic organic compounds that achieve similar adsorption enhancement without the safety hazards and handling difficulties associated with alcoholic solvents

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

Solution Approach 2:

The patent converts the harmful flammability and handling difficulties of alcohols into benefits by using biscationic organic compounds that are safer, non-flammable, and easier to handle while maintaining or improving adsorption efficiency

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

4Productivity

If high quantities of proteolytic enzyme are used to digest proteins, then protein removal is improved, but the cost increases due to need for high-quality nuclease-free enzyme

Engineering Contradiction:
Improveprotein removal efficiencyVSAvoidenzyme cost
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent changes the concentration parameter by using low concentrations of biscationic organic compounds that enable effective protein removal without requiring high quantities of expensive proteolytic enzymes, thereby reducing enzyme cost while maintaining protein removal efficiency

Inventive Principle:
Principle #35Parameter 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 efficient nucleic acid purification at lower salt concentrations, reducing the need for hazardous reagents and simplifying the purification process while maintaining high adsorption efficiency, as demonstrated by the biscationic compounds' ability to promote adsorption under acidic conditions and in the presence of magnetic particles.

Implementation Method 1

adsorbing nucleic acids to a solid phase (e.g. a silica matrix) in the presence of a chaotropic substance

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a direct ionic interaction between the -Si-OH groups of the silica matrix and the phosphate-di-ester groups of the nucleic acid backbone becomes possible

Methodology Applied
Scientific EffectIonic interaction: Ion Repulsion/Attraction

Implementation Method 3

the chaotropic substance effects removal of water molecules from the hydrate shell of dissolved nucleic acid molecules as well as from the surface of the solid phase

Methodology Applied
Scientific EffectDehydration: Desiccation

Implementation Method 4

separating the solid phase with the adsorbed nucleic acid from the solution

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP1992693B1Absorption of nucleic acids to solid phases under low-salt conditions
Publication Date: 2014.09.03 ROCHE DIAGNOSTICS GMBH
  • EP1992693B1 patent drawingFigure 1
  • EP1992693B1 patent drawingFigure 2
  • EP1992693B1 patent drawingFigure 3

AI summary

Biscationic organic compounds are disclosed which promote adsorption of nucleic acids from an aqueous solution to a solid phase such as silica. Adsorption takes place under low salt conditions. Further disclosed are methods and kits suitable for nucleic acid isolation from aqueous solutions.