Digital PCR Nucleic Acid Length Quantification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for analyzing the size of nucleic acids, particularly those derived from the same source, are limited in their ability to accurately quantify the relative abundance of nucleic acids of different lengths in a sample, especially in complex biological samples like maternal plasma or cancer patient samples, where differentiation between fetal and maternal DNA or tumor-specific sequences is challenging.
Innovation Solution
A method involving microfluidics and digital PCR using multiple sets of primers to amplify and distinguish nucleic acid fragments of varying lengths, allowing for the precise detection and quantification of specific sequences through primer extension reactions and mass spectrometry, enabling the analysis of nucleic acid size distribution in a sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrophoresis is used for size analysis of nucleic acids, then size differentiation is achieved, but quantification precision of relative abundance is limited
Solution Approach 1:
The sample is divided into multiple discrete reaction compartments (wells or droplets), with each compartment containing a small number of nucleic acid molecules. This segmentation enables digital counting of molecules by detecting amplification products in each compartment, achieving precise quantification of relative abundance without the limitations of bulk electrophoresis methods.
2Measurement precision
If multiple sets of primers are used to amplify and distinguish nucleic acid fragments of varying lengths, then size distribution analysis precision is improved, but reaction complexity increases
Solution Approach 1:
Multiple sets of primers are designed to amplify different size ranges of nucleic acid fragments, with each primer set serving a specific function for detecting particular length ranges. This multi-functional approach enables comprehensive size distribution analysis within a single digital PCR assay, improving precision while managing complexity through systematic primer design.
Solution Approach 2:
The analysis transitions from single-dimensional detection to multi-dimensional detection by incorporating multiple primer sets that target different amplicon sizes. This allows simultaneous measurement of size distribution across multiple dimensions, providing comprehensive characterization of nucleic acid fragments in the sample.
3Measurement precision
If digital PCR with multiple primer sets is used, then detection accuracy of specific sequences is improved, but assay time and processing steps increase
Solution Approach 1:
Multiple primer sets are combined into a single digital PCR reaction mixture, allowing simultaneous amplification and detection of multiple target sequences and size ranges in one assay. This merging of multiple detection functions into a single reaction reduces total assay time compared to performing separate assays for each target.
Solution Approach 2:
The digital PCR process enables continuous amplification and detection of multiple targets simultaneously across all reaction compartments, maximizing the utilization of each reaction cycle. This continuous multi-target detection eliminates the need for sequential processing, reducing overall assay time while maintaining high detection accuracy.
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 allows for the accurate measurement and differentiation of nucleic acid fragments of different sizes, enhancing the detection of fetal DNA in maternal plasma and identifying tumor-specific sequences, thereby improving diagnostic accuracy in non-invasive prenatal testing and cancer monitoring.
Implementation Method 1
amplification reactions are carried out in each and every one of the multiple equal fractions
Implementation Method 2
the polynucleotide sequence or sequences that have been produced by the amplification reaction(s) within each one of the multiple equal fractions of the sample are detected and distinguished from each other
Data Source
AI summary
The present invention provides a method for analyzing nucleic acids for their lengths and relative abundance in a sample, based on digital amplification of individual template molecules. This invention has many applications, including those in noninvasive prenatal diagnosis, transplantation monitoring, and the detection and monitoring of cancers and virus-associated diseases.