Isothermal Nucleic Acid Amplification Specificity Control
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Solution Overview
Problem
Current nucleic acid amplification methods require complicated temperature control and use of special enzymes or primers, leading to inefficiencies and difficulties in primer design, especially under isothermal conditions.
Innovation Solution
A method involving a two-step temperature incubation process using a reaction solution with deoxynucleotide triphosphates, DNA polymerase with strand displacement activity, and oligonucleotide primers, where the solution is first incubated at a temperature for high specificity and then at a higher temperature for high efficiency, without the need for special enzymes or primers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal cycler is used to perform denaturation, annealing, and elongation at different temperatures, then nucleic acid amplification can be achieved, but complicated temperature control is required
Solution Approach 1:
The invention changes the temperature parameter from multiple discrete temperatures (PCR method) to a single isothermal condition. By using Bst DNA polymerase with strand displacement activity at a constant temperature of 60-65°C, the complex temperature cycling is replaced with a simple isothermal reaction, resolving the contradiction between amplification reliability and temperature control complexity
Solution Approach 2:
The invention extracts and utilizes the strand displacement activity of Bst DNA polymerase to replace the need for temperature cycling. The polymerase's inherent ability to displace strands at isothermal conditions removes the requirement for thermal cyclers, simplifying the device while maintaining amplification effectiveness
2Device complexity
If isothermal amplification methods like LAMP are used, then temperature control is simplified, but at least 4 types of primers recognizing 6 specific sites are required making primer design extremely difficult
Solution Approach 1:
The invention changes the primer configuration from multiple specialized primers (LAMP requiring 4 types) to a simple primer pair. By utilizing the strand displacement activity of Bst DNA polymerase, the system achieves isothermal amplification with only forward and reverse primers, dramatically simplifying primer design while maintaining isothermal operation
Solution Approach 2:
The invention makes a simple primer pair perform the function that previously required 4 different primers. The strand displacement mechanism allows the basic primer pair to initiate and sustain amplification without requiring additional specialized primers, making the method universally applicable and easy to design
3Device complexity
If SDA method is used for isothermal amplification, then temperature control is simplified, but exonuclease as well as polymerase must be used leading to high costs and complex primer design
Solution Approach 1:
The invention extracts and utilizes only the strand displacement activity of Bst DNA polymerase, removing the requirement for exonuclease entirely. This single-enzyme system performs both the synthesis and strand displacement functions, reducing enzyme requirements and costs while simplifying the overall reaction system
Solution Approach 2:
The Bst DNA polymerase performs multiple functions: it acts as both the synthesizing enzyme and the strand-displacing enzyme. This multi-functional single-enzyme system replaces the two-enzyme requirement of SDA, reducing complexity and cost
4Reliability
If PCR method is used to amplify target nucleic acid, then amplification can be achieved, but time loss increases as the number of cycles increases
Solution Approach 1:
The invention creates a continuous amplification process by eliminating the pause periods between temperature transitions required in PCR. The isothermal strand displacement mechanism allows uninterrupted synthesis and displacement cycles to occur continuously at constant temperature, significantly reducing the time required for multiple amplification cycles
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
This approach enhances specificity and reduces dispersion in amplification rates, allowing for rapid and sensitive nucleic acid amplification without complex temperature control or special primer design.
Implementation Method 1
a step of incubating a reaction solution containing at least one type of deoxynucleotide triphosphate, at least one type of DNA polymerase having strand displacement activity, at least two types of oligonucleotide primers, and a nucleic acid fragment acting as a template
Implementation Method 2
incubating the reaction solution at temperature (T1)... incubating the reaction solution at temperature (T2) that is higher than the temperature (T1)
Data Source
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AI summary
It is an object of the present invention to provide a method for amplifying a nucleic acid, which does not require complicated temperature control and which can be carried out without using special enzyme or special primers. The present invention provides a method for amplifying a nucleic acid, which comprises the following steps (1) and (2): (1) a step of incubating a reaction solution containing at least one type of deoxynucleotide triphosphate, at least one type of DNA polymerase, at least two types of oligonucleotide primers, and a nucleic acid fragment acting as a template, at temperature (T1); and (2) a step of incubating the reaction solution at temperature (T2) that is higher than the temperature (T1) and is between 50°C or higher and 100°C or lower, following the step (1).