Polycation Substrate for cfDNA Extraction from Blood

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Solution Overview

Problem

Current nucleic acid extraction methods from whole blood samples often result in genomic nucleic acid contamination due to upfront lysis, which complicates the isolation of cell-free nucleic acids (cfNA) and reduces their yield.

Innovation Solution

A nucleic acid extraction material comprising a substrate with a polycation, such as a cationic copolymer of quaternized 1-vinylimidazole and N-vinylpyrrolidone, bonded to its surface, which selectively captures and elutes cell-free deoxyribonucleic acids (cfDNA) from whole blood samples with minimal genomic nucleic acid contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If upfront lysis is performed to release nucleic acids from cells, then total nucleic acid yield is improved, but genomic nucleic acid contamination increases

Engineering Contradiction:
Improvenucleic acid yieldVSAvoidgenomic nucleic acid contamination
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The invention extracts only the desired cell-free nucleic acids from the sample while leaving cellular material intact. The polycation selectively binds cfDNA and cfRNA in the supernatant without requiring cell lysis, thereby extracting the target analyte while excluding genomic contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies different treatment conditions to different components of the sample. The polycation is applied to the supernatant under specific conditions (pH 4.0-6.0, 0.1-1.0 mg/mL concentration) that create selective binding affinity for cell-free nucleic acids while maintaining cellular integrity and preventing genomic DNA release.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If selective capture of cell-free nucleic acids is achieved without lysis, then genomic contamination is reduced, but capture efficiency may be worsened

Engineering Contradiction:
Improvegenomic nucleic acid contaminationVSAvoidcfNA capture efficiency
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The invention optimizes multiple parameters to enhance selective capture: polycation concentration (0.1-1.0 mg/mL), pH (4.0-6.0), incubation time (5-30 minutes), and temperature (4°C to room temperature). These parameter combinations maximize cfNA binding efficiency while maintaining selectivity against cellular nucleic acids.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a copolymer consisting of quaternized 1-vinylimidazole and N-vinylpyrrolidone units. This composite structure combines the cationic charge density of quaternized imidazole for strong nucleic acid binding with the hydrophilic properties of N-vinylpyrrolidone for enhanced solubility and reduced non-specific binding, achieving both efficiency and selectivity.

Inventive Principle:
Principle #40Composite materials

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

The method effectively increases the yield of cfDNA from whole blood samples by reducing genomic nucleic acid contamination and allows for efficient elution and processing of cfNA, enhancing diagnostic applications such as non-invasive prenatal testing and cancer detection.

Implementation Method 1

a polycation, such as a cationic copolymer of quaternized 1-vinylimidazole and N-vinylpyrrolidone, bonded to its surface, which selectively captures and elutes cell-free deoxyribonucleic acids (cfDNA)

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

which selectively captures and elutes cell-free deoxyribonucleic acids (cfDNA) from whole blood samples with minimal genomic nucleic acid contamination

Methodology Applied
Scientific EffectElectrostatic interaction disruption: Electrostatics

Data Source

PatentEP3652314B1Nucleic acid extraction materials and methods
Publication Date: 2023.08.23 ILLUMINA INC
  • EP3652314B1 patent drawingFigure 1A~1C
  • EP3652314B1 patent drawingFigure 2~3
  • EP3652314B1 patent drawingFigure 4

AI summary

An example of a nucleic acid extraction material includes a substrate. The nucleic acid extraction material also includes a polycation bonded to at least a portion of a surface of the substrate. The polycation consists of a polymer of a quaternized monomer selected from the group consisting of a quaternized 1-vinylimidazole monomer and a quaternized dimethylaminoethyl methacrylate monomer, or a copolymer of a neutral monomer and the quaternized monomer.