Temperature-Selectable FRET Cassettes for Single-Channel Multiplexing
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Solution Overview
Problem
Existing nucleic acid multiplex detection methods require specialized equipment or hardware changes to maximize detection capacity, and there is a need for approaches that can be easily adapted to automated testing platforms without such modifications.
Innovation Solution
A FRET cassette reporter system using 5′ flap FRET cassette oligonucleotides and masking oligonucleotides with different melting temperatures, combined with FEN-1 endonuclease, to distinguish different nucleic acid analytes in a single multiplex reaction using a single fluorescence detection channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple nucleic acid analytes are detected in a single reaction mixture using traditional multiplex methods, then detection capacity is improved, but specialized equipment or hardware changes are required
Solution Approach 1:
The patent utilizes temperature as a parameter to distinguish between different nucleic acid analytes. Different masking oligonucleotides are designed with different melting temperatures (Tm values), allowing them to bind and release at specific temperature ranges. This enables the differentiation of multiple analytes using a single fluorescence detection channel on standard PCR instrumentation, eliminating the need for specialized equipment while maintaining high detection capacity.
Solution Approach 2:
The patent introduces masking oligonucleotides as intermediary molecules that temporarily bind to fluorescently-labeled probe fragments. These masking oligos act as mediators that prevent fluorescence signal generation for certain analytes at lower temperatures, while allowing signal generation for other analytes at higher temperatures. This intermediary mechanism enables multiplex detection without requiring multiple fluorescence channels or specialized hardware.
2Productivity
If different assay formats are used to accommodate multiplexing capabilities, then detection of multiple analytes is improved, but reagent costs and complexity increase
Solution Approach 1:
The patent employs a universal detection system where a single fluorescence detection channel can distinguish between multiple nucleic acid analytes through temperature-dependent masking oligo binding. Instead of requiring multiple specialized reagent sets or detection channels, the system uses temperature-controlled binding of masking oligos with different Tm values to selectively enable or disable fluorescence signals for different analytes. This universal approach reduces reagent complexity while maintaining multiplex detection capability.
3Ease of manufacture
If a single detectable label is used when exact identity of analytes is not required, then cost is reduced, but ability to distinguish between analytes is lost
Solution Approach 1:
The patent introduces dynamic temperature control to a system that otherwise uses a single static fluorescent label. By varying the temperature during detection, the system dynamically changes which masking oligos are bound vs. released, thereby dynamically enabling or disabling fluorescence signals for different analytes. This dynamic approach allows a single fluorescent label to provide differentiated information about multiple analytes without requiring multiple distinct labels, maintaining cost effectiveness while preserving analyte identity distinction.
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 efficient and cost-effective multiplex nucleic acid detection by distinguishing different analytes through temperature-dependent fluorescence quenching, compatible with standard PCR instrumentation.
Implementation Method 1
at least a portion of the masking oligonucleotide is specifically hybridizable to the 5′ flap portion of the FRET cassette oligonucleotide, wherein hybridization of the masking oligonucleotide to the cassette cleaved flap forms a duplex
Implementation Method 2
hybridization of the masking oligonucleotide to the cassette cleaved flap forms a duplex having a first melting temperature exhibiting a first melting peak
Implementation Method 3
fluorescence emission from the first fluorophore moiety in the duplex
Implementation Method 4
fluorescence emission from the first fluorophore moiety in the duplex is quenched by the second quencher moiety
Data Source
AI summary
A multiplexed nucleic acid amplification and detection system useful for detecting the presence of multiple specific nucleic acid sequences or single nucleotide polymorphisms (i.e., “SNPs”) in a temperature-dependent fashion using only a single fluorescence detection channel of a nucleic acid analyzer. The technique can be carried out using standard PCR instrumentation equipped for fluorescence detection or monitoring.