Surface-Based Nucleic Acid Detection via Thermal Convection
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Solution Overview
Problem
Existing nucleic acid detection technologies face challenges in rapid point-of-care (PoC) detection of pathogen biomarkers due to difficulties in designing enzymes that are fast, high-fidelity, and robust to chemicals/inhibitors, and enzyme-free approaches often require expensive and bulky equipment for molecular sensitivity, limiting their use in resource-limited conditions.
Innovation Solution
A device comprising a surface with oligonucleotide complexes, where one oligonucleotide is irreversibly linked to the surface and another is complementary but not, with a fluorescence quencher, allowing for enzyme-free amplification and detection of nucleic acids using a fluidic reaction chamber with differential temperature zones and convection flow for efficient mixing and hybridization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If enzyme-based nucleic acid amplification is used, then amplification speed and specificity are improved, but device complexity and cost increase due to need for temperature cycling equipment
Solution Approach 1:
The patent extracts the temperature cycling function from the amplification process by using isothermal conditions. The system removes the need for complex thermal cycler equipment by performing DNA amplification at a constant temperature through engineered DNA polymerases that function optimally at isothermal conditions, thereby simplifying the device while maintaining amplification capability.
Solution Approach 2:
The patent changes the temperature parameter from variable (cycling) to constant (isothermal). By engineering DNA polymerases with shifted optimal temperature profiles and using buffer systems that maintain stable activity at constant temperatures, the system achieves amplification without temperature cycling, reducing device complexity while preserving productivity.
2Device complexity
If enzyme-free nucleic acid detection is used, then device complexity is reduced, but detection sensitivity decreases requiring expensive and bulky equipment
Solution Approach 1:
The patent performs preliminary amplification of the target nucleic acid using isothermal enzymatic amplification before detection. This pre-amplification step increases the concentration of target molecules to levels detectable by simple optical equipment, eliminating the need for sensitive but complex detection systems while maintaining overall system simplicity.
Solution Approach 2:
The patent introduces engineered DNA polymerases and specially designed oligonucleotide probes as intermediaries that enable detection with simple equipment. These intermediaries convert the detection task into measuring optical properties (fluorescence, absorbance) that can be detected by basic photodetectors rather than requiring sophisticated molecular detection equipment.
3Measurement precision
If conventional nucleic acid amplification is used, then detection sensitivity is improved, but false positives increase due to DNA breathing events
Solution Approach 1:
The patent applies local quality control by designing specific structural features in the oligonucleotide probes and amplicon regions. The probes include mismatch bases at specific positions and the amplicon design incorporates regions with different melting characteristics, creating local variations in stability that prevent spurious amplification while allowing specific targets to amplify reliably.
Solution Approach 2:
The patent implements preliminary anti-action by designing the amplification system to preemptively prevent false positives through controlled denaturation conditions. The isothermal amplification uses carefully engineered polymerases and buffer conditions that maintain specific DNA structures, preventing premature strand separation and non-specific amplification before the actual amplification process begins.
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, enzyme-free amplification and detection of nucleic acids with improved sensitivity and specificity, reducing the need for costly equipment and enhancing usability in resource-limited settings, while minimizing false positives through solid-phase separation and thermal convection flow.
Implementation Method 1
a second oligonucleotide comprising a second DNA sequence and a third DNA sequence, wherein the second DNA sequence is complementary to the first DNA sequence and is hybridized thereto
Implementation Method 2
convection flow for efficient mixing and hybridization
Implementation Method 3
Each of said first oligonucleotides may comprise a fluorescent moiety, and each of said second oligonucleotides may comprise a fluorescence quencher
Data Source
AI summary
The present disclosure provides methods, composition and devices for performing convection-based PCR and non-enzymatic amplification of nucleic acid sequences. Techniques and reagents employed in these methods include toehold probes, strand displacement reactions, Rayleigh-Benard convection, temperature gradients, multiplexed amplification, multiplexed detection, and DNA functionalization, in open and closed systems, for use in nucleic tests and assays.