Nucleic Acid Purification via Anionic Surfactant Precipitation
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Solution Overview
Problem
Current methods for isolating and purifying nucleic acids, particularly DNA, from biological samples are time-consuming and involve multiple steps, often requiring precipitation or binding to a solid matrix, which complicates the process and can lead to mechanical and chemical degradation of DNA.
Innovation Solution
A method involving a lysis buffer with an anionic surfactant, such as dodecyl sulfate, and monovalent or divalent ions to keep DNA in solution, followed by size-exclusion chromatography for purification, reducing the number of steps and minimizing degradation, while maintaining high purity and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional purification methods (precipitation or binding to solid matrix) are used, then DNA can be separated from contaminants, but the process becomes time-consuming and complex with multiple steps
Solution Approach 1:
The invention extracts and removes contaminants (proteins, RNA, metabolites) from the lysate using specific reagents before DNA precipitation. Contaminants are selectively removed in separate steps: proteins are precipitated with cold ethanol and acetone, RNA is degraded with RNase, and metabolites are removed with perchloric acid. This extraction approach allows DNA to be purified without requiring complex multi-step binding and washing procedures, reducing overall purification time while maintaining high quality.
Solution Approach 2:
The purification process is segmented into distinct functional steps: lysis, contaminant removal (proteins, RNA, metabolites), and DNA precipitation. Each step targets specific contaminants separately rather than using a single complex binding-wash-elute cycle. This segmentation simplifies the overall process by breaking down the purification into manageable, sequential operations that can be performed rapidly.
2Reliability
If multiple purification steps are performed, then DNA purity is improved, but mechanical and chemical degradation of DNA increases
Solution Approach 1:
The invention performs preliminary removal of contaminants (proteins, RNA, metabolites) from the lysate before DNA precipitation. By removing these contaminants in advance through selective precipitation and enzymatic degradation, the DNA can be precipitated directly from a cleaner solution without requiring subsequent binding to solid matrices and multiple washing steps. This preliminary action protects DNA integrity while achieving high purity.
Solution Approach 2:
The invention replaces mechanical binding-to-solid-matrix systems with chemical precipitation methods. DNA is precipitated directly from solution using ethanol or isopropanol in the presence of monovalent cations, avoiding the need for solid-phase binding, washing, and elution. This substitution eliminates mechanical stress on DNA molecules while maintaining effective purification through selective solubility differences.
3Productivity
If simple and fast techniques (high temperature incubation or protease digestion) are used, then purification time is reduced, but enzyme-inhibiting contaminants (high salt load) remain
Solution Approach 1:
The invention extracts and removes salt and other soluble contaminants from the lysate using perchloric acid precipitation and cold ethanol/acetone treatment before DNA precipitation. These extraction steps eliminate enzyme-inhibiting contaminants while maintaining rapid processing. The contaminants are removed in the same workflow without requiring separate additional purification steps, thus preserving both speed and downstream application compatibility.
4Reliability
If salting-out methods are used to precipitate proteins, then protein removal is achieved, but additional RNase treatment and repeated alcohol precipitations are necessary
Solution Approach 1:
The invention merges multiple contaminant removal functions into a unified workflow. Protein precipitation with cold ethanol and acetone is combined with RNA degradation by RNase treatment and metabolite removal with perchloric acid in a sequential but integrated process. DNA precipitation is then performed from this pre-cleared lysate in a single step. This merging of functions reduces the number of separate purification cycles needed while maintaining effective protein removal efficiency.
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 allows for rapid isolation of high-quality, purified DNA with fewer steps, reducing mechanical and chemical stress, and enabling direct use in downstream applications like PCR without additional processing, while maintaining or exceeding the quality of existing methods.
Implementation Method 1
mixing the sample with a lysis buffer comprising an anionic surfactant, but being essentially free of a chelating or complexing agent
Implementation Method 2
precipitating the surfactant ions from the lysate preferably by adding to the lysate a solution comprising monovalent ions of alkali metals and/or divalent ions of alkaline earth metals
Implementation Method 3
followed by size-exclusion chromatography for purification
Implementation Method 4
precipitating the surfactant ions from the lysate preferably by adding to the lysate a solution comprising monovalent ions of alkali metals and/or divalent ions of alkaline earth metals
Data Source
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AI summary
The present invention relates to a method for isolating and purifying nucleic acids, preferably comprising genomic DNA, from biological samples comprising the steps of lysing the sample using a lysis buffer comprising a source of anionic surfactant ions, optionally disintegrating the RNA present in the lysate, precipitating the surfactant ions from the lysate, and separating the nucleic acids from the precipitate and further contaminants by size-exclusion chromatography. The invention furthermore relates to a lysis buffer, a method of lysing cells and a kit for the isolation and purification of nucleic acids.