Exponential Background Subtraction for High-Resolution Melting Curve Genotyping

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Solution Overview

Problem

Existing methods for high-resolution melting curve analysis face challenges in accurately removing background fluorescence, especially when using unlabeled probes and small amplicons, leading to erroneous genotyping and mutation detection due to interference from background noise.

Innovation Solution

The implementation of exponential background subtraction (EBS) method, which calculates and subtracts the background signal from melting curve data using exponential fitting at specific temperature points, allowing for accurate normalization and enhancement of melting curve analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional background subtraction methods are used in melting curve analysis, then the process is simple, but the accuracy of genotyping and mutation detection deteriorates due to background fluorescence interference

Engineering Contradiction:
Improvegenotyping accuracyVSAvoidbackground subtraction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional linear or manual background subtraction methods with an exponential mathematical model (EBS) that automatically fits and subtracts background fluorescence. This substitution of the background subtraction mechanism with an exponential function-based system resolves the contradiction by providing both high accuracy in genotyping and automated processing without manual intervention.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces exponential parameters (amplitude, decay constant, offset) to model the background fluorescence behavior across different temperature points. By changing from simple linear subtraction to exponential parameter-based modeling, the system achieves superior background removal accuracy while the automated fitting process manages the increased complexity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high-resolution melting curve analysis is performed rapidly, then productivity increases, but measurement precision deteriorates due to insufficient data collection time

Engineering Contradiction:
Improvemelting curve analysis speedVSAvoidmelting curve resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary exponential background subtraction on the raw melting curve data before further analysis. This preliminary action of removing background noise early in the process enables subsequent high-resolution measurements to be performed more rapidly, as the signal-to-noise ratio is already optimized, resolving the contradiction between speed and precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The exponential background model acts as an intermediary that processes the raw fluorescence data, separating background signal from sample signal. This intermediary processing step enables rapid yet precise analysis by providing cleaned data that can be quickly interpreted without sacrificing resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If unlabeled probes are used in melting analysis, then ease of operation improves, but measurement precision deteriorates due to background fluorescence interference

Engineering Contradiction:
Improveprobe simplicityVSAvoidsignal detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the background fluorescence component from the total signal using exponential background subtraction. This extraction of the unwanted background signal allows unlabeled probes to be used without their inherent background interference compromising measurement precision, thus resolving the contradiction between operational simplicity and detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful background fluorescence that naturally occurs with unlabeled probes into a quantifiable exponential model that can be subtracted. By modeling the background as an exponential function of temperature, the system transforms the previously harmful interference into a useful computational step that enhances rather than degrades measurement precision.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

EBS significantly improves the accuracy and specificity of genotyping and mutation scanning by isolating the sample melting curve signal from background noise, even at lower temperatures, enhancing the ability to distinguish between genotypes and variants.

Implementation Method 1

Fluorescence techniques that are homogeneous and do not require the addition of reagents after commencement of amplification or physical sampling of the reactions for analysis are attractive

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

Studies with UV absorbance often required hours to collect high-resolution data

Methodology Applied
Scientific EffectUV absorbance: Absorption (EM radiation)

Data Source

PatentEP3168766B1Genotyping method for a plurality of samples
Publication Date: 2023.08.16 UNIV OF UTAH RES FOUND
  • EP3168766B1 patent drawingFigure 1A~1B
  • EP3168766B1 patent drawingFigure 2A~2B
  • EP3168766B1 patent drawingFigure 3A

AI summary

The invention provides a method for clustering melting profiles of a plurality of nucleic acid samples, comprising measuring the fluorescence of each nucleic acid sample as a function of temperature to produce a respective raw melting curve for each respective nucleic acid sample, each respective sample comprising a respective nucleic acid and a molecule that binds the respective nucleic acid to form a respective fluorescently detectable complex, and clustering genotypes of the plurality of nucleic acid samples to form a plurality of clusters of melting curves, wherein the clustering is hierarchically achieved upon assigning a distance between each pair of melting profiles.