Fluorescent PCR Library Quantitation for Accurate NGS Loading
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Solution Overview
Problem
Existing methods for quantitating and qualifying DNA libraries in next-generation sequencing (NGS) are inaccurate and time-consuming, relying on estimations, UV spectrophotometry, and qPCR, and fail to account for varying fragment lengths and adapter presence, leading to inconsistent concentration and size determinations.
Innovation Solution
A method involving fluorescence-labeled PCR primers that attach a predetermined number of fluorophores to DNA fragments, allowing for accurate quantitation and qualification by detecting fluorescent signals, followed by removing unincorporated primers and generating a standard curve for precise concentration adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UV spectrophotometry or qPCR is used to quantify DNA libraries, then concentration can be determined, but the measurements are inaccurate and time-consuming due to failing to account for varying fragment lengths and adapter presence
Solution Approach 1:
The invention extracts and measures only the fluorescently labeled adapter sequences that are universally present on all DNA fragments in the library. By using PCR to amplify and then quantifying only these labeled adapter regions through fluorescence, the method eliminates the need to account for varying fragment lengths and other non-adapter components, providing accurate concentration measurements quickly without the time-consuming complexities of traditional methods
Solution Approach 2:
The fluorescently labeled adapter sequences serve as an intermediary marker for quantitation. Instead of measuring total DNA directly (which varies in composition and length), the method uses these standardized fluorescent adapters as a proxy. The fluorescence signal from these intermediaries provides an accurate, time-efficient measure of library concentration that is independent of fragment length variations
2Measurement precision
If clusters are placed further apart to enable accurate sequence determination, then sequencing accuracy improves, but the cost per cluster increases due to reduced processing efficiency
Solution Approach 1:
The invention performs preliminary quantitation of the DNA library concentration using fluorescently labeled adapters before the sequencing run. This advance measurement allows for precise calculation of the dilution factor needed to achieve optimal cluster spacing on the flow cell. By knowing the exact concentration beforehand, users can prepare samples with the correct dilution to ensure clusters are properly spaced for accurate sequencing while maximizing the number of clusters per run, thus maintaining high productivity
3Ease of operation
If existing quantitation methods are used, then concentration can be estimated, but the library concentration and size determinations are inconsistent leading to inefficient sequencing
Solution Approach 1:
The fluorescently labeled adapter sequences serve multiple functions: they enable PCR amplification of the library, provide universal binding sites for primers, and simultaneously serve as quantitative markers for concentration determination. This multi-functionality eliminates the need for separate quantitation steps using different methods, providing consistent and reliable concentration data that simplifies the overall sequencing preparation workflow while improving reliability
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
Enables accurate determination of DNA fragment concentration and size without relying on UV spectrophotometry or qPCR, ensuring efficient sequencing by ensuring appropriate cluster spacing and reducing sequencing costs.
Implementation Method 1
amplifying the DNA fragments by polymerase chain reaction (PCR) in the presence of primers each labeled with a fluorophore... detecting a fluorescent signal produced by the amplified DNA fragments
Data Source
AI summary
Described herein are methods, compositions, and kits for library quantitation and qualification. Some embodiments relate to a method of library quantitation. For example, the method may include providing DNA fragments, amplifying the DNA fragments by polymerase chain reaction (PCR) in the presence of primers each labeled with a fluorophore. In these instances, only a predetermined number of fluorophores are attached to each DNA fragment. The method may further include detecting a fluorescent signal produced by the amplified DNA fragments and calculating a number of the amplified DNA fragments based on the detected fluorescent signal.