Toehold-Mediated DNA Strand Displacement for Nucleic Acid Detection
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Solution Overview
Problem
Conventional methods for detecting nucleic acid target sequences, such as RNA and single-stranded DNA, are expensive and not suitable for point-of-care applications due to the need for expensive machinery and materials like fluorescent probes.
Innovation Solution
A method combining toehold-mediated DNA strand displacement and RNA toehold switch technologies, embedded in porous materials like paper, allowing for portable and cost-effective detection of nucleic acid target sequences using a retainer and release strand apparatus and an RNA sequence with a sequestered ribosome binding site and transducer sequence for reporter protein expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Taqman assay methods are used for DNA target sequence detection, then detection accuracy is achieved, but cost increases significantly (multiple times more expensive)
Solution Approach 1:
The patent employs disposable paper-based substrates with embedded nucleic acid probes instead of expensive reusable fluorescent detection systems. The paper substrate serves as a single-use, low-cost platform that eliminates the need for costly fluorescent probes and specialized detection equipment, achieving both cost reduction and maintained detection accuracy through the inherent properties of the paper matrix and embedded oligonucleotides.
Solution Approach 2:
The invention replaces the complex mechanical and optical systems of conventional Taqman assays (fluorescent probes, thermal cyclers, detection machinery) with a simplified chemical-biological system based on hybridization on paper. The detection mechanism shifts from fluorescence-based optical detection to colorimetric or visual detection of hybridization products, eliminating expensive equipment while preserving analytical capability.
2Reliability
If conventional detection methods with expensive machinery are used, then reliable detection is achieved, but device complexity and portability are compromised
Solution Approach 1:
The patent extracts the essential detection function from complex laboratory machinery and concentrates it into a simple paper-based device. By removing the need for thermal cyclers, fluorescent detectors, and other expensive equipment, the invention isolates the core hybridization-detection mechanism onto a portable substrate that maintains reliability through careful design of the paper matrix and embedded probes.
Solution Approach 2:
The invention utilizes the porous structure of paper as the detection platform. The paper matrix provides a high-surface-area support for immobilizing nucleic acid probes, enables efficient sample loading and reagent diffusion, and facilitates visual readout. This porous material substitution eliminates complex machinery while maintaining reliable detection through the physical properties of the paper substrate.
3Measurement precision
If fluorescent probes and expensive materials are used, then detection sensitivity is improved, but cost and accessibility for point-of-care applications worsen
Solution Approach 1:
The patent employs disposable paper-based substrates with embedded nucleic acid probes instead of expensive fluorescent detection systems. The paper substrate serves as a single-use, low-cost platform that eliminates the need for costly fluorescent probes and specialized detection equipment, achieving both cost reduction and maintained detection accuracy through the inherent properties of the paper matrix and embedded oligonucleotides.
Solution Approach 2:
The invention changes the detection parameter from fluorescence intensity (requiring expensive probes and equipment) to colorimetric or visual signals detectable by the naked eye or simple readers. This parameter transformation maintains detection sensitivity while eliminating the need for fluorophores and sophisticated instrumentation, making the assay accessible for point-of-care use in resource-limited settings.
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 accurate and inexpensive detection of nucleic acid target sequences at ambient temperatures, reducing the need for expensive equipment and reagents, and allowing for simultaneous detection of multiple sequences in a multiplex array.
Implementation Method 1
The first portion of the retainer strand may be complementary to a first portion of the release strand. Accordingly, the retainer strand and the release strand may be bound together at the first portion.
Implementation Method 2
a second portion of the retainer strand may be complementary to the nucleic acid target sequence
Implementation Method 3
a toehold portion of the RNA sequence may be complementary to the second portion of the second nuclei acid strand of the Toehold-mediated DNA strand displacement apparatus
Data Source
AI summary
Disclosed is a method of facilitating detection of a nucleic acid target sequence. The method may include utilizing a toehold-mediated DNA strand displacement apparatus comprising a portion complementary to the nucleic acid target sequence. The method may further include utilizing a RNA toehold switch comprising a RNA sequence. Further, the toehold portion of the RNA sequence may be complementary to a portion of the toehold-mediated DNA strand displacement apparatus. The method may further include combining the toehold-mediated DNA strand displacement apparatus and the RNA toehold switch in an assay, such that the two are never in direct physical contact with each other. Accordingly, a sample containing the nucleic acid target sequence on the substrate may displace a nucleic acid strand from the toehold-mediated DNA strand displacement apparatus and bind a portion of it to the RNA toehold switch resulting in expression of the reporter protein.