Selective DNA Stains for RNA-Free Detection

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Solution Overview

Problem

Current stains are not selective for double-stranded DNA in the presence of RNA or single-stranded DNA, making it difficult to detect double-stranded DNA in samples containing these nucleic acids.

Innovation Solution

Development of chemical compounds with specific structures that exhibit high selectivity for double-stranded DNA, showing fluorescence when bound to it but not when bound to RNA or in the absence of nucleic acids, allowing for their use in detecting double-stranded DNA in samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional stains such as ethidium bromide are used, then DNA can be detected, but the stains also bind to RNA and single-stranded DNA, reducing measurement precision

Engineering Contradiction:
Improveselectivity for double-stranded DNAVSAvoidbinding to multiple nucleic acid types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by designing stains with specific molecular structures (cyanine dyes with particular substituents) that create localized binding preferences for double-stranded DNA. The chemical structure is modified at specific positions (R1, R2, R3, R4 groups) to confer selective affinity for dsDNA over RNA and ssDNA, allowing the stain to distinguish between different nucleic acid types based on its local chemical properties

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by systematically varying chemical parameters of the stain molecules (substituents on the cyanine dye core structure) to optimize binding selectivity. By changing the chemical composition and structural parameters of the stain, the patent achieves enhanced discrimination between double-stranded DNA and other nucleic acids, directly addressing the measurement precision issue

Inventive Principle:
Principle #35Parameter changes

2Reliability

If stains lacking selectivity are used, then detection can be performed, but purification steps are required, increasing device complexity and time

Engineering Contradiction:
Improveaccurate DNA quantitationVSAvoidpurification step requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by incorporating selectivity into the stain design itself, so that the staining step inherently performs the function of differentiation without requiring prior purification. The selective stain binds preferentially to double-stranded DNA in the presence of RNA and single-stranded DNA, eliminating the need for separate purification steps that would otherwise be required to achieve accurate DNA quantitation

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If non-selective stains are used, then nucleic acids can be detected, but RNA interference occurs, reducing measurement precision

Engineering Contradiction:
ImproveDNA detection accuracy in presence of RNAVSAvoidRNA interference
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potential harm of RNA presence into a benefit by designing stains that exploit structural differences between RNA and double-stranded DNA. Rather than trying to eliminate RNA, the selective stain uses its optimized chemical structure to distinguish and bind preferentially to dsDNA, transforming the interference problem into a selective detection advantage

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

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

These compounds enable accurate detection of double-stranded DNA in samples containing RNA or single-stranded DNA by exhibiting significant fluorescence only when bound to double-stranded DNA, facilitating precise quantitation and identification.

Implementation Method 1

stains that exhibit higher fluorescence when contacted with double stranded DNA than when contacted with RNA and/or single stranded DNA

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP1885718B1Fluorescent chemical compounds having high selectivity for double stranded DNA, and methods for their use
Publication Date: 2017.03.15 LIFE TECHNOLOGIES CORP

AI summary

Chemical compounds having a high selectivity for double stranded DNA over RNA and single stranded DNA are disclosed. The chemical compounds are stains that become fluorescent upon illumination and interaction with double stranded DNA, but exhibit reduced or no fluorescence in the absence of double stranded DNA. The compounds can be used in a variety of biological applications to qualitatively or quantitatively assay DNA, even in the presence of RNA.