Bifunctional Fluorescent PNA Probe Melting Curve Analysis
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Solution Overview
Problem
Current methods for diagnosing microsatellite instability (MSI) are cumbersome, costly, and lack sensitivity, particularly in detecting low-level MSI, and are limited by the use of dinucleotide repeat markers with low sensitivity and specificity, and require lengthy capillary electrophoresis processes.
Innovation Solution
A method using bifunctional fluorescent PNA probes with reporters and quenchers that selectively bind to microsatellite markers, allowing for high-sensitivity detection of base mutations through melting curve analysis, enabling the identification of MSI even at low rates, by differentiating binding forces based on sequence variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capillary electrophoresis methods are used for MSI diagnosis, then the diagnosis can be performed using standard protocols, but the test time is lengthy and costs are high
Solution Approach 1:
The patent replaces the mechanical capillary electrophoresis separation system with a fluorescent melting curve analysis system. The PNA probe-based fluorescent melting analysis eliminates the need for lengthy electrophoresis separation while providing equivalent or superior MSI detection accuracy through temperature-based dissociation curves that reveal microsatellite instability patterns.
Solution Approach 2:
The patent changes the detection parameter from electrophoretic mobility to fluorescent melting temperature. By monitoring the melting curve characteristics of PNA-probe hybridized to microsatellite markers, the system rapidly identifies MSI patterns without the time-consuming electrophoresis process, reducing test time while maintaining diagnostic reliability.
2Reliability
If conventional methods are used for MSI detection, then standard procedures can be followed, but sensitivity for low-level MSI detection is insufficient
Solution Approach 1:
The patent employs PNA probes with locally optimized sequences that specifically target microsatellite regions. The probes are designed with precise melting temperatures and fluorescent characteristics that enhance local detection sensitivity, allowing differentiation of low-level MSI patterns that conventional methods cannot detect.
Solution Approach 2:
The patent uses PNA probes pre-designed with optimal binding characteristics that cushion against the low signal intensity of low-level MSI. The probes' stable hybridization and sharp melting transitions provide a built-in amplification effect that enhances detection sensitivity before analysis, enabling reliable detection of MSI at rates as low as 5%.
3Adaptability or versatility
If dinucleotide repeat markers are used, then the markers can be analyzed, but the sensitivity and specificity are low
Solution Approach 1:
The patent develops PNA probes that can universally detect both mononucleotide and dinucleotide repeat markers with high sensitivity. The probes are designed to work across different marker types, providing versatile analysis capability while achieving superior detection precision compared to conventional marker-specific approaches.
Solution Approach 2:
The patent combines PNA probe technology with fluorescent labeling and melting curve analysis to create a composite detection system. This composite approach integrates the specificity of PNA hybridization with the sensitivity of fluorescent detection, overcoming the limitations of using dinucleotide markers alone and achieving high sensitivity and specificity simultaneously.
4Reliability
If conventional fluorescent PCR and capillary electrophoresis are used, then the two-step process can be completed, but the procedure is cumbersome and costly
Solution Approach 1:
The patent merges the PCR amplification and detection steps into a single fluorescent melting curve analysis procedure. The PNA probes are added directly to the PCR reaction, and the melting analysis is performed on the same sample without separate electrophoresis, simplifying the procedure from a two-step process to an integrated one-step method that reduces complexity and cost while maintaining accuracy.
Solution Approach 2:
The patent uses fluorescently labeled PNA probes as intermediaries that bridge PCR amplification and detection. The probes hybridize to amplified microsatellite products and provide direct fluorescent signals that can be analyzed by melting curve, eliminating the need for separate electrophoresis and reducing procedural complexity while maintaining diagnostic 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
This approach significantly enhances the sensitivity and specificity of MSI detection, reducing test time and costs, and allows for the analysis of MSI at rates as low as 5%, surpassing conventional methods in accuracy and efficiency.
Implementation Method 1
mixing the target nucleic acid with a PNA probe to hybridize the PNA probe with the target nucleic acid
Implementation Method 2
denaturating the hybridized product, while changing a temperature, to obtain a melting curve
Implementation Method 3
the PNA probe has a reporter and a quencher coupled thereto
Data Source
AI summary
Disclosed are a method for analyzing a melting curve using bi-functional fluorescent PNA probes, a method for diagnosing microsatellite instability (MSI) using the same, and a kit for diagnosing microsatellite instability (MSI) using the same. More particularly, disclosed are a method for analyzing a melting curve, based on the structure of fluorescent PNA probes that bind with different binding forces depending on the number of base mutations deleted using the fluorescent PNA probes capable of specifically binding to regions where the same base is repeated, and a method for rapidly and accurately detecting and analyzing microsatellite instability (MSI) by detecting gene mutation of microsatellite markers caused by base deletion in regions where the same base is repeated using the analysis method and analyzing the number of base mutations thus obtained. The method and kit can analyze the presence of deletion of microsatellite marker genes with high sensitivity and specificity using five microsatellite markers of Quasi loci, thus having advantages of reducing costs, shortening a test time, and the like, as compared to conventional MSI diagnostic methods.