Isothermal Recombinase Polymerase Amplification for Clonal Sequencing
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Solution Overview
Problem
Conventional nucleic acid amplification methods require extreme denaturing conditions, leading to reduced yields and increased contamination in multiplex clonal amplification, as they render templates substantially single-stranded, complicating downstream applications like sequencing.
Innovation Solution
The method employs recombinase polymerase amplification (RPA) and template walking under isothermal conditions, allowing for the clonal amplification of multiple templates within the same reaction mixture without denaturing, producing monoclonal amplicons suitable for sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional nucleic acid amplification methods are used, then amplification can be achieved, but extreme denaturing conditions reduce yield and increase contamination
Solution Approach 1:
The patent changes the temperature parameter from extreme denaturing conditions (94-95°C) to isothermal conditions (60-70°C), and changes the chemical environment by replacing harsh denaturants with milder buffering conditions. This allows amplification to proceed without extreme denaturing, maintaining template integrity and reducing contamination while preserving yield
Solution Approach 2:
The patent replaces the mechanical/thermal denaturation mechanism with a biochemical mechanism using recombinase enzymes and polymerases that can function at moderate temperatures. The recombinase-polymerase system substitutes for the thermal denaturation step, enabling strand separation and amplification without extreme heat, thereby reducing contamination risk
2Ease of operation
If extreme denaturing conditions are applied, then template denaturation is achieved, but templates become substantially single-stranded complicating downstream applications
Solution Approach 1:
The patent changes the temperature parameter from extreme heat (94-95°C) to moderate isothermal conditions (60-70°C), allowing denaturation to occur gently without complete strand separation. This maintains templates in a partially double-stranded state that is compatible with downstream applications like sequencing while still achieving sufficient denaturation for amplification
Solution Approach 2:
The patent employs periodic addition of recombinase and polymerase enzymes in a controlled sequence, allowing incremental denaturation and amplification cycles. This periodic enzymatic action achieves progressive template denaturation without requiring extreme conditions, preserving template integrity for downstream use
3Productivity
If multiplex clonal amplification is performed, then process efficiency is improved, but contamination increases and yield reduces
Solution Approach 1:
The patent segments the amplification process into distinct spatial compartments using microarray wells or flow cell chambers. Each compartment performs independent clonal amplification of different templates, preventing cross-contamination between multiplex reactions while maintaining high process efficiency through parallel processing of multiple samples simultaneously
Solution Approach 2:
The patent introduces immobilized primers attached to solid supports (beads, microarray surfaces) as intermediaries that capture and amplify templates in place. This intermediary approach allows multiplex amplification without template mixing, as each template is captured and amplified at its designated location, reducing contamination while maintaining high throughput
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 yield and reduces contamination by maintaining templates in a double-stranded state, enabling efficient clonal amplification of multiple templates simultaneously, improving the quality of sequencing data.
Implementation Method 1
The method employs recombinase polymerase amplification (RPA) and template walking under isothermal conditions, allowing for the clonal amplification of multiple templates within the same reaction mixture without denaturing
Data Source
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AI summary
In some embodiments, the present teachings provide methods for nucleic acid amplification, comprising forming a reaction mixture, and subjecting the reaction mixture to conditions suitable for nucleic acid amplification. In some embodiments, methods for nucleic acid amplification include subjecting the nucleic acid to be amplified to partially denaturing conditions. In some embodiments, methods for nucleic acid amplification include amplifying without fully denaturing the nucleic acid that is amplified. In some embodiments, the methods for nucleic acid amplification employ an enzyme that catalyzes homologous recombination and a polymerase. In some embodiments, methods for nucleic acid amplification can be conducted in a single reaction vessel. In some embodiments, methods for nucleic acid amplification can be conducted in a single continuous liquid phase of a reaction mixture, without need for compartmentalization of the reaction mixture or immobilization of reaction components. In some embodiments, methods for nucleic acid amplification comprise a amplifying at least one polynucleotide onto a surface under isothermal amplification conditions, optionally in the presence of a polymer. The polymer can include a sieving agent and/or a diffusion-reducing agent.