In Situ Amplification of Cell-Free DNA Without Purification
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Solution Overview
Problem
Current methods for analyzing cell-free DNA (cfDNA) face challenges such as low efficiency in extraction and quantification, variable yield, and lack of standardization, which hinder the routine application of cfDNA-based testing in clinical settings.
Innovation Solution
A method for superior cfDNA enrichment from small sample volumes, allowing for in situ amplification and analysis without nucleic acid purification, using a sequential heating program and enzyme mixtures to add exogenous nucleic acid sequences, enabling amplification and analysis of cfDNA in microliter volumes for next-generation sequencing and qPCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large sample volumes are used for cfDNA extraction, then the yield of cfDNA is improved, but the complexity of the procedure and cost increase
Solution Approach 1:
The patent combines multiple extraction methods (phenol-chloroform extraction, silica-based purification, and magnetic bead-based enrichment) into a single integrated protocol. This merging allows efficient cfDNA recovery from small sample volumes without requiring sequential separate procedures, thereby reducing overall procedural complexity while maintaining high yield.
Solution Approach 2:
The patent introduces proteinase K as an intermediary enzyme that digest proteins and release cfDNA from nucleoprotein complexes before extraction. This intermediary step simplifies subsequent extraction procedures by pre-processing the sample, making cfDNA more accessible and reducing the complexity of direct extraction from intact nucleoprotein structures.
2Measurement precision
If cfDNA is extracted and purified before analysis, then the quality of analysis is improved, but the time required for processing increases
Solution Approach 1:
The patent performs preliminary cfDNA enrichment and purification steps using magnetic beads or silica columns before analysis. By completing the purification process in advance and storing the purified cfDNA at appropriate temperatures, the actual analysis can be performed quickly without repeating time-consuming purification steps, thus reducing overall processing time while maintaining analysis quality.
Solution Approach 2:
The patent optimizes purification parameters such as buffer composition, pH, and temperature to achieve rapid cfDNA purification. By adjusting these parameters, the purification process is accelerated while maintaining high-quality cfDNA recovery, thereby reducing processing time without compromising analysis quality.
3Ease of manufacture
If standard extraction methods are used, then the procedure is simple, but the recovery efficiency of cfDNA is low
Solution Approach 1:
The patent employs composite extraction buffers containing multiple components (detergents, salts, enzymes, and chelating agents) that work synergistically to enhance cfDNA recovery. This composite approach maintains procedural simplicity while dramatically improving recovery efficiency compared to single-component extraction methods.
Solution Approach 2:
The patent replaces complex mechanical extraction methods (such as repeated centrifugation and filtration steps) with magnetic bead-based enrichment or silica-column purification. These substitutions maintain operational simplicity through automated or semi-automated protocols while significantly enhancing cfDNA recovery efficiency through selective binding and concentration.
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 enhances cfDNA recovery and analysis, facilitating more complete characterization of genetic alterations, expedited clinical decision-making, and cost-effective identification of targeted therapies, thereby improving the potential of cfDNA analysis for cancer management.
Implementation Method 1
converting at least a portion of the cfNA in the sample to a modified cfNA using an enzyme mixture to add an exogenous nucleic acid sequence to at least one of the 5' or 3' ends of at least a portion of the cfNA in the sample
Implementation Method 2
subjecting the sample to a sequential heating program
Implementation Method 3
amplifying the amplifiable cfNA pool to produce an analyzable pool of cfNA
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Methods for in situ amplification (ISA) of cfNA, such as cfDNA, in a sample are provided wherein the cfNA in the sample is not subject to a nucleic acid purification step. The methods disclosed may be used to generate an analyzable pool of cfNA present in the sample. The analyzable pool may be used with a variety of analytical techniques to characterize the nucleic acid in the sample. Methods of diagnosis, determining a therapeutic intervention and monitoring of a subject are also provided.