Magnetic Bead cfDNA Extraction for Non-Invasive Prenatal Screening
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Solution Overview
Problem
Current methods for detecting chromosomal abnormalities in fetuses are invasive, carry risks of miscarriage, and have limitations in accuracy and sensitivity, particularly in detecting fetal aneuploidies.
Innovation Solution
The use of magnetic beads that reversibly bind cell-free DNA (cfDNA) for improved isolation and separation from liquid biological samples, allowing for non-invasive prenatal testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional invasive methods (amniocentesis, CVS) are used for fetal genetic testing, then diagnostic accuracy is improved, but procedure-related risk of miscarriage increases
Solution Approach 1:
The patent uses cell-free DNA from maternal plasma as an intermediary to indirectly detect fetal chromosomal abnormalities. Instead of directly sampling fetal cells through invasive procedures, the method analyzes fetal DNA fragments that circulate in maternal blood, eliminating the need for invasive fetal sampling while maintaining diagnostic accuracy.
Solution Approach 2:
The patent replaces mechanical invasive procedures (amniocentesis, CVS) with a biochemical analysis method. Instead of physically penetrating the uterus to obtain fetal samples, the system uses molecular biology techniques to detect fetal DNA markers in maternal plasma, substituting mechanical intervention with laboratory-based detection.
2Ease of operation
If current maternal serum screening markers are used, then non-invasive testing is achieved, but detection accuracy and sensitivity are limited with false positive rates up to 5-6%
Solution Approach 1:
The patent changes the analytical parameters by using next-generation sequencing (NGS) to deeply sequence maternal plasma DNA, analyzing over 100,000 reads per chromosome. This high-depth sequencing enables precise detection of chromosomal abnormalities with sensitivity exceeding 99%, dramatically improving upon traditional serum marker screening while maintaining non-invasive sampling.
Solution Approach 2:
The patent performs preliminary DNA extraction and library preparation from maternal plasma before sequencing analysis. By systematically preparing and quality-controlling the DNA samples in advance, the method ensures high-quality input for sequencing, thereby achieving high detection accuracy while maintaining the non-invasive advantage of maternal plasma sampling.
3Reliability
If cfDNA isolation methods are improved for quantity and quality, then sensitivity and reproducibility of assay are enhanced, but extraction process complexity increases
Solution Approach 1:
The patent segments the cfDNA isolation process into distinct modular steps: (1) magnetic bead-based DNA capture, (2) wash steps to remove contaminants, (3) elution of purified DNA, and (4) quality control assessment. This segmentation allows each step to be optimized independently and facilitates automation while maintaining high reliability and reproducibility.
Solution Approach 2:
The patent replaces complex mechanical centrifugation and precipitation methods with magnetic bead-based capture technology. The magnetic beads selectively bind to DNA through complementary strand hybridization, enabling simple magnetic separation rather than complex mechanical processes, thereby reducing extraction process complexity while improving DNA quantity and quality consistency.
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 the quantity, quality, and consistency of cfDNA isolation, improving the accuracy of fetal fraction determination and the detection of fetal aneuploidies, while reducing sample-to-sample variation.
Implementation Method 1
contacting a liquid biological sample containing cfDNA with a plurality of magnetic beads that reversibly bind to DNA
Implementation Method 2
contacting the outer surface of the vessel containing the elution solution containing the eluted cfDNA and the magnetic beads to a magnetic plate and collecting the elution solution containing the eluted cfDNA. In some embodiments, the magnetic plate comprises a ring magnet that causes the magnetic beads to adhere to the vessel walls
Data Source
AI summary
Provided herein are methods and systems for cell-free DNA extraction from liquid biological samples. The methods can be employed for determination of fetal DNA fraction and non- invasive prenatal screening of fetal aneuploidies and analyses of other types of cell-free DNA.