Carboxylate-Mediated Nucleic Acid Size Selection

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Solution Overview

Problem

Current methods for size-selective nucleic acid isolation, such as gel electrophoresis and PEG-based buffers, are cumbersome, time-consuming, and prone to bead carry-over, which complicates downstream reactions and reduces the efficiency of sequencing data quality in next-generation sequencing applications.

Innovation Solution

A method using a carboxylate compound to selectively bind target nucleic acid molecules to a matrix, such as borosilicate glass or silica surfaces, allowing for efficient size selection by controlling the binding of nucleic acids based on molecular size, with the option of using small-molecule modulators like ammonium acetate to enhance specificity and reduce non-target binding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gel electrophoresis is used for size-selective nucleic acid isolation, then separation precision is improved, but operation complexity and time consumption increase

Engineering Contradiction:
Improvesize selection precisionVSAvoidisolation procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical gel electrophoresis system with a chemical binding system using carboxylate compounds. Instead of using electric fields and gel matrices to separate nucleic acids by size, the invention uses carboxylate-nucleic acid complex formation in solution followed by selective precipitation, substituting a complex mechanical separation process with a simpler chemical treatment protocol.

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

Solution Approach 2:

The carboxylate compound acts as an intermediary that mediates the size-selective isolation process. By forming transient complexes with nucleic acids of specific sizes, the carboxylate enables selective precipitation without requiring direct physical separation methods like gel electrophoresis, thus simplifying the overall procedure while maintaining size selection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If PEG-based buffers are used for size-selective isolation, then isolation speed is improved, but bead carry-over and downstream reaction interference increase

Engineering Contradiction:
Improveisolation speedVSAvoidbead carry-over and contamination
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a disposable carboxylate treatment protocol that does not require reusable magnetic beads or other solid support materials. The carboxylate-nucleic acid complexes are formed in solution and selectively precipitated, eliminating the need for bead-based systems that can cause carry-over contamination in downstream applications.

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

Solution Approach 2:

The invention extracts the size selection function from bead-based systems and implements it through direct chemical treatment with carboxylate compounds. By removing the bead component entirely and using only soluble carboxylate agents, the method achieves size selection without the harmful bead carry-over effect while maintaining rapid processing speed.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If carboxylate compound concentration is increased to improve binding specificity, then size selection precision is improved, but non-target binding and loss of target nucleic acid increase

Engineering Contradiction:
Improvesize selection specificityVSAvoidtarget nucleic acid loss
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent optimizes the carboxylate compound concentration to achieve the optimal balance between binding specificity and target nucleic acid recovery. By carefully controlling the concentration parameter of the carboxylate agent, the method achieves high size selection specificity while minimizing non-target binding and preventing loss of target nucleic acid through excessive binding.

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 rapid, reliable, and high-efficiency size selection of nucleic acids, reducing background noise in sequencing data and improving the quality of sequencing libraries by selectively isolating target molecules while minimizing contamination.

Implementation Method 1

contacting a sample comprising nucleic acid molecules with a matrix in the presence of a carboxylate compound, wherein the carboxylate compound is present in a sufficient concentration that the target nucleic acid molecules selectively bind to the matrix

Methodology Applied
Scientific EffectMolecular binding/Adsorption: Adsorption

Data Source

PatentEP3344767B1Small-molecule mediated size selection of nucleic acids
Publication Date: 2024.08.07 QIAGEN SCIENCES LLC
  • EP3344767B1 patent drawingFigure 1
  • EP3344767B1 patent drawingFigure 2
  • EP3344767B1 patent drawingFigure 3

AI summary

Provided are methods and compositions for negatively and positively selecting for different size nucleic acid (e.g., DNA or RNA) fragments on borosilicate glass fiber membranes, silica and metal oxide surfaces such that only those fragments falling within a desired size range are obtained.