Multiplex miRNA Detection via Differential Fluorescence Melting
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Solution Overview
Problem
Current methods for detecting multiple microRNAs (miRNAs) are limited by requiring multiple qPCR reactions, leading to quantification bias, high costs, and longer turn-around times, and are not suitable for clinical adoption due to complexity and need for skilled personnel.
Innovation Solution
The use of fluorescent probe/quencher oligo relationships in qPCR systems, where probes are quenched when bound to quencher oligos and become fluorescent when unbound, allowing for multiplex detection of up to 10-15 targets using 5 fluorescent channels by measuring fluorescence at different melting temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple qPCR reactions are used to detect multiple miRNAs, then detection specificity is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent combines multiple miRNA detection targets into a single qPCR reaction by using different fluorescent probes (FAM, VIC, HEX, CY5) that can be detected in one reaction. This merging approach maintains detection specificity through probe design while reducing the number of separate reactions needed, directly resolving the contradiction between specificity and complexity.
Solution Approach 2:
The patent employs a universal qPCR reaction system that can simultaneously detect multiple miRNA targets through multiplex fluorescent probes. The single reaction system serves multiple detection functions, eliminating the need for separate specialized reactions for each miRNA while preserving detection accuracy.
2Measurement precision
If multiple qPCR reactions are used to detect multiple miRNAs, then detection accuracy is improved, but turn-around time increases
Solution Approach 1:
By merging multiple miRNA detections into a single concurrent qPCR reaction using fluorescent probes with different emission wavelengths, the patent reduces turn-around time while maintaining quantification accuracy. The simultaneous detection of multiple targets in one reaction eliminates sequential processing time.
Solution Approach 2:
The patent enables continuous detection of multiple miRNA targets throughout the single qPCR reaction cycle, rather than completing separate reactions sequentially. The fluorescent probes continue to detect their respective targets simultaneously across amplification cycles, maximizing useful action within the reaction time.
3Measurement precision
If stem-loop RT primer method is used, then miRNA detection sensitivity is improved, but quantification bias increases
Solution Approach 1:
The patent applies local quality by designing miRNA-specific fluorescent probes with unique sequences and fluorophores for each target. This localized probe design ensures that each miRNA is detected with high sensitivity through its specific probe while avoiding the quantification bias introduced by universal primers, as each probe is optimized for its specific target sequence.
4Adaptability or versatility
If poly(A) tailing and adapter ligation methods are used, then miRNA detection versatility is improved, but detection efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the complex poly(A) tailing and adapter ligation steps from the detection process by using direct miRNA-specific fluorescent probes that bind to the miRNA sequence without requiring these additional modification steps. This extraction maintains versatility in detecting various miRNA types while significantly improving detection efficiency by removing unnecessary procedural steps.
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 provides sensitive, specific, and cost-effective PCR-based assays with reduced bias for target detection and quantification, enabling high-throughput multiplex detection of multiple miRNAs in a single reaction.
Implementation Method 1
a fluorescent probe or primer in close proximity to (e.g., hybridized or otherwise bound to) the quencher oligo is dark (i.e., quenched), and when free from the quencher oligo, e.g., free in solution or bound to a target nucleic acid is fluorescent (i.e., unquenched)
Implementation Method 2
a detection probe and a quencher oligonucleotide... capable of hybridizing to each other
Data Source
AI summary
Compositions and methods for quantitative detection of target nucleic acids, such as miRNAs are disclosed. The methods are especially advantageous for single-color multiplex detection of two or more targets simultaneously (e.g., in the same reaction). The methods can involve optional reverse transcription followed by amplification performed with universal primers, fluorophore-labeled detection probes, and quencher oligonucleotides for quenching fluorescence of any detection probe not bound to a target molecule. The methods employ differential stability of detection probe-quencher oligonucleotide complexes, and by extension, differential fluorescence at various temperatures to distinguish between different target molecules.