FFPE Nucleic Acid Purification via Phase Separation
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Solution Overview
Problem
Current methods for genotyping and gene expression analysis of tissue samples are hindered by the inability to efficiently extract nucleic acids from formalin-fixed paraffin-embedded (FFPE) samples, which are commonly used in histological analysis and archival storage, limiting the study of disease mechanisms and biomarkers.
Innovation Solution
A method involving heating FFPE samples in the presence of an ionic detergent to separate a paraffin phase and an aqueous phase, followed by adding a protease to the aqueous phase for incubation, which facilitates the purification of nucleic acids using techniques such as TRIZOL precipitation, anion exchange chromatography, or ChargeSwitch® purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional extraction methods are used on FFPE samples, then the samples can be processed, but the nucleic acid extraction efficiency is poor and contamination is high
Solution Approach 1:
The extraction process is divided into distinct phases: paraffin phase and aqueous phase separation. The paraffin phase contains contaminants while the aqueous phase contains the purified nucleic acids, achieving physical segmentation of harmful components from the target molecules.
Solution Approach 2:
The method extracts nucleic acids specifically from the aqueous phase after paraffin removal. This selective extraction isolates the desired nucleic acid component while leaving paraffin and other contaminants in the separated paraffin phase, improving purity.
2Adaptability or versatility
If FFPE samples are used instead of frozen samples, then archival storage and histological analysis are enabled, but nucleic acid extraction becomes difficult
Solution Approach 1:
The method changes physical parameters (temperature, phase state) to facilitate extraction. Heating the sample causes paraffin to melt and separate from the aqueous phase, transforming the extraction process from a difficult chemical procedure to a manageable physical separation.
Solution Approach 2:
The aqueous phase acts as an intermediary medium that selectively solubilizes nucleic acids while excluding paraffin. This intermediate phase allows easy separation of contaminants from the target molecules through simple phase separation.
3Productivity
If rapid extraction is achieved through heating, then productivity increases, but temperature control becomes critical
Solution Approach 1:
The method exploits the phase transition of paraffin from solid to liquid at elevated temperatures. By heating to a specific temperature range, paraffin melts and separates from the aqueous phase, enabling rapid extraction without requiring extreme temperatures or prolonged processing.
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 method enables the rapid and reliable separation and purification of nucleic acids from FFPE samples, improving the quality and yield of RNA and DNA for genetic manipulation and analysis, such as RT-PCR, and reducing contaminating DNA or RNA, thus aiding in disease diagnosis and therapeutic approaches.
Implementation Method 1
heating the sample at about 50-85° C. for about 1-60 minutes in the presence of an ionic detergent to produce a paraffin phase and an aqueous phase
Implementation Method 2
adding a protease to the aqueous phase and incubating the aqueous phase at about 25-80° C. for about 5-60 minutes
Data Source
AI summary
Disclosed are rapid and reproducible methods for separating and purifying nucleic acids from paraffin-containing tissue samples. The disclosed methods involve a melting step, where paraffin-containing tissue samples are heated in the presence of a detergent, causing the paraffin to melt and tissue sample cells to lyse. From the resulting two-phase mixture (i.e., a paraffin phase and an aqueous phase), the aqueous phase is collected for purification of nucleic acid. Protease(s) can be used at one or more points in the separation process to facilitate tissue cell lysis and/or degrade proteins that could degrade nucleic acid or interfere with subsequent genetic manipulation or analysis.