Isothermal Rolling Circle Amplification for RNA Detection
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Solution Overview
Problem
Current methods for detecting RNA, such as real-time PCR and rolling circle amplification, are complex, costly, and require specialized equipment, making them unsuitable for simple or clinical use, and they suffer from limitations in amplification and detection efficiency.
Innovation Solution
A kit and method involving hybridization of target RNA with single-stranded circular DNA and a primer for rolling circle amplification, followed by detection using a guanine quadruplex-binding reagent like thioflavin T derivatives, which allows for specific detection of amplified sequences without the need for temperature cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time PCR method is used for RNA detection, then detection accuracy is improved, but device complexity and operation complexity increase
Solution Approach 1:
The patent replaces the complex thermal cycling mechanical system of PCR with an isothermal rolling circle amplification system. The amplification reaction proceeds at a constant temperature (37°C) using phi29 DNA polymerase, eliminating the need for temperature cycling equipment while maintaining high detection accuracy through sequence-specific primer binding and rolling circle amplification of the target RNA.
2Measurement precision
If real-time PCR method is used for RNA detection, then detection accuracy is improved, but operation complexity increases
Solution Approach 1:
The patent replaces complex temperature cycling operations with simple isothermal incubation at 37°C. The rolling circle amplification proceeds automatically under constant conditions without requiring programmed temperature changes, significantly simplifying the operational procedure while maintaining detection accuracy through specific primer-template hybridization and enzymatic amplification.
3Ease of operation
If rolling circle amplification method is used for RNA detection, then operation simplicity is improved, but amplification efficiency decreases
Solution Approach 1:
The patent employs a preliminary action by designing a circular DNA template with a specific structure that includes a primer binding site and a rolling circle amplification region. The template is pre-configured with complementary sequences that enable efficient primer annealing and subsequent rolling circle amplification, thereby improving amplification efficiency while maintaining operational simplicity.
Solution Approach 2:
The patent optimizes amplification efficiency by changing key parameters: using phi29 DNA polymerase with high processivity, maintaining optimal dNTP concentrations, controlling Mg2+ levels for enzyme activity, and designing primers with appropriate Tm values. These parameter optimizations enable rapid and efficient rolling circle amplification while keeping the procedure simple and isothermal.
4Ease of operation
If rolling circle amplification method is used for RNA detection, then operation simplicity is improved, but detection efficiency decreases
Solution Approach 1:
The patent employs color/fluorescence changes for detection by incorporating a fluorophore-labeled primer or detection probe that emits fluorescence when bound to the amplified RNA product. The rolling circle amplification generates multiple copies of the target sequence, and the accumulated fluorescent signal provides high detection efficiency and sensitivity, enabling visualization of amplification success without complex equipment.
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 simple detection of target RNA with improved sensitivity and specificity, using a reagent that only fluoresces in the presence of guanine quadruplex structures, reducing the need for expensive equipment and simplifying the detection process.
Implementation Method 1
hybridizing the target RNA with a single-stranded circular DNA and a primer to form a complex of these three molecules
Implementation Method 2
detecting a detection reagent-binding sequence (for example, guanine quadruplex-containing sequence) contained in the amplification product using a detection reagent such as a thioflavin T (ThT) derivative
Implementation Method 3
a detection reagent such as a thioflavin T (ThT) derivative
Data Source
AI summary
An RNA detection kit comprising: (i) a single-stranded circular DNA template containing: a sequence of 10 to 30 bases complementary to a first portion of a target RNA; a primer-binding sequence of 7 to 8 bases adjacent to 5′-side thereof; and a sequence complementary to a detection reagent-binding sequence such as a guanine quadruplex-forming sequence; (ii) an oligonucleotide primer containing: a sequence of 8 to 15 bases complementary to a second portion adjacent to the 3′-side of the first portion of the target RNA; and a sequence of 7 to 8 bases adjacent to 3′-side thereof and complementary to the primer-binding sequence of the single-stranded circular DNA template; and (iii) a detection reagent such as a guanine quadruplex-binding reagent; is provided.