Tethered Enzyme Nucleic Acid Detection for Low-Concentration Targets
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Solution Overview
Problem
Existing nucleic acid detection methods face challenges due to side-products interfering with amplification reactions and low sensitivity, especially when target sequences are present at very low concentrations, leading to inaccurate analysis.
Innovation Solution
A method using tethered enzymes, specifically capture oligonucleotides with tailored sequences and lengths, coupled with polymerase and luciferase, to produce a bioluminescent signal through isothermal extension reactions, excluding deoxy-adenosine triphosphate from the dNTP mixture, and utilizing tethered enzymes on solid supports for enhanced stability and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly sensitive nucleic acid amplification systems are used to detect low-concentration target sequences, then detection sensitivity is improved, but side-products interfere with the amplification reaction and lower specificity
Solution Approach 1:
The detection system is segmented into multiple functional components: capture probes for specific target binding, tethered enzymes for controlled amplification, and bioluminescent reporters for detection. This segmentation allows each component to perform its function independently, reducing interference from side-products while maintaining high sensitivity for low-concentration targets
Solution Approach 2:
Tethered enzymes act as intermediaries between the capture probes and the detection system. These enzymes are immobilized on solid supports, creating a controlled interface that enhances specificity by ensuring that only targets bound to capture probes undergo amplification, while preventing spurious reactions from side-products
2Device complexity
If isothermal amplification techniques are used to avoid thermocycling, then device complexity is reduced, but amplification efficiency and sensitivity may be compromised
Solution Approach 1:
The system uses isothermal conditions with optimized temperature (e.g., 37°C) and enzymatic parameters to achieve efficient amplification without thermocycling. By changing the operational parameters from temperature-cycling to constant temperature with enhanced enzyme activity, the system maintains amplification efficiency while dramatically reducing device complexity
Solution Approach 2:
The tethered enzymes on solid supports perform self-contained amplification at isothermal conditions, generating sufficient signal amplification without external temperature control. The system serves itself through the inherent catalytic activity of the enzymes, eliminating the need for complex thermocycling 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
The method provides rapid, sensitive, and specific nucleic acid detection with minimal interference, enabling qualitative and quantitative analysis of target nucleic acids, including low-concentration sequences, and allows for multiplex assays without temperature cycling.
Implementation Method 1
contacting a sample with a capture oligonucleotide molecule complementary to at least a portion of the target nucleic acid molecule so that the capture oligonucleotide molecule hybridizes to a complementary portion of the target nucleotide molecule and forms a double-stranded nucleic acid molecule
Implementation Method 2
The polymerase extension mixture is subjected to conditions under which the target nucleic acid molecule is extended isothermally and releases free phosphates
Implementation Method 3
the adenosine triphosphates produced from the free phosphates are metabolized with a luciferase to produce a bioluminescent readout signal
Data Source
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AI summary
The present application relates to methods of detecting a target nucleic acid molecule in a sample. The method includes providing a sample containing a target nucleic acid molecule and a capture oligonucleotide molecule. In one embodiment, the capture oligonucleotide molecule has (i) a length of 30-60 base pairs, (ii) a 4-8 base pair overhang on its 3' end, (iii) a 5' tail, (iv) a target-specific portion between the 3' end and the 5' tail, (v) a deoxy-adenosine diphosphate content of 40-50%, (vi) no deoxy thymidine phosphate in the 3' end or the 5' tail, and (vii) the 3' end and the 5' tail having an ATP content which is 40-50% of that of the capture oligonucleotide molecule. In another aspect of the method of detecting, certain reagents are coupled to a solid support. The present application also relates to compositions and kits useful in carrying out the methods of the present application.