Sulfonated DNA Purification Using Acidic Silica Binding
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Solution Overview
Problem
Conventional methods for bisulfite conversion of DNA suffer from sample loss, low recovery rates, and reproducibility issues, particularly for cytosine-rich targets, and require extensive processing times, compromising the effectiveness of DNA methylation detection.
Innovation Solution
The method involves binding sulfonated DNA to silica supports in an acidic solution with a pH less than or equal to the isoelectric point of the sulfonated DNA and silica, using chaotropic salts like guanidine hydrochloride, followed by washing, desulfonation, and elution to enhance DNA recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional silica spin columns or ethanol purification methods are used for bisulfite conversion, then DNA purification is achieved, but sample loss occurs and recovery rates decrease
Solution Approach 1:
The patent changes the pH parameter of the binding buffer to acidic conditions (pH 2-4), which fundamentally alters the interaction between sulfonated DNA and silica. This parameter change enables strong binding of sulfonated DNA to silica supports, preventing sample loss during purification steps and significantly improving recovery rates compared to conventional neutral or alkaline conditions
Solution Approach 2:
The patent introduces acidic conditions as an intermediary mechanism that facilitates the binding between sulfonated DNA and silica supports. The acidic environment acts as a mediator that enables the interaction to occur, allowing for effective purification without the sample loss associated with conventional methods
2Productivity
If conventional bisulfite conversion methods are used, then methylation detection is performed, but processing time extends to days
Solution Approach 1:
The patent implements continuous binding of sulfonated DNA to silica supports throughout the purification process, eliminating the need for multiple separate steps and buffer changes. This continuous action significantly reduces processing time while maintaining detection accuracy
Solution Approach 2:
The patent segments the conventional multi-step purification process into a single integrated binding step using acidic conditions, where all necessary separations and purifications occur simultaneously during one operation, dramatically reducing the overall processing time
3Reliability
If conventional purification methods are used, then DNA is recovered, but reproducibility is compromised
Solution Approach 1:
The patent establishes acidic pH conditions (pH 2-4) as a standardized parameter for the binding buffer, providing consistent and reproducible binding conditions across different experiments. This standardized parameter approach eliminates the variability and reproducibility issues associated with conventional methods while maintaining high recovery rates
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 significantly improves DNA recovery and robustness in bisulfite treatment processes, facilitating efficient detection of methylation markers in various sample types, including cytosine-rich targets, with reduced processing time.
Implementation Method 1
disrupting the hydrogen bond of water with DNA to promote silica-DNA interaction
Implementation Method 2
binding sulfonated DNA to silica supports in an acidic solution, wherein the acidic solution has a pH less than or equal to an isoelectric point pH(I) of the sulfonated DNA and the silica support
Implementation Method 3
increasing chaotropic salt concentration thereby disrupting the hydrogen bond of water with DNA to promote silica-DNA interaction
Implementation Method 4
spontaneous deamination of the sulfonated reaction intermediate which results in sulfonated uracil
Implementation Method 5
desulfonating uracil under alkaline conditions to form uracil
Data Source
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AI summary
The present disclosure provides methods and systems for purification of chemically modified, specifically, sulfonated DNA. Additionally, the disclosure provides methods and systems for bisulfite conversion with improved purification of sulfonated DNA using silica supports, such as silica beads, and acidic conditions for binding sulfonated DNA to silica surfaces.