Linear Nucleic Acid Primer Rules for Specific Cell-Free DNA Amplification
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Solution Overview
Problem
Existing primer design methods for in vitro transcription (IVT) of DNA templates are inexact, leading to nonspecific DNA amplification, primer-homodimer formation, and primer hairpin formation, requiring multiple iterations to achieve effective DNA synthesis, which is time and purity of the amplicon.
Innovation Solution
A set of rules for selecting nucleic acid primers, including specific length, GC content, terminal nucleotides, and thermodynamic properties, to create a filtered primer library, followed by validation using qPCR, ensuring efficient hybridization and amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional primer design guidelines are used, then hybridization efficiency is enhanced, but primer-homodimer and hairpin formation occur leading to nonspecific amplification
Solution Approach 1:
The patent applies parameter changes by systematically varying primer design parameters including length (18-25 nucleotides), GC content (40-60%), melting temperature (55-65°C), and avoiding specific sequence patterns that promote secondary structure formation. This optimized parameter set resolves the contradiction by achieving high hybridization efficiency while minimizing harmful primer interactions.
Solution Approach 2:
The patent converts the harmful effect of primer self-complementarity into a beneficial design criterion by explicitly calculating and optimizing for low hairpin formation propensity and low homodimer formation propensity using thermodynamic parameters. This transforms what was previously an unavoidable harm into a controllable design parameter that ensures specific amplification.
2Manufacturing precision
If multiple iterations of primer design are performed, then amplification purity is improved, but time consumption increases
Solution Approach 1:
The patent applies preliminary action by performing comprehensive in silico validation of primer candidates before experimental use. This includes predicting melting temperatures, assessing hairpin formation propensity, evaluating homodimer formation propensity, and checking for nonspecific binding using computational algorithms. This preliminary computational screening eliminates the need for multiple experimental iterations, achieving high amplification purity in a single design cycle.
Solution Approach 2:
The patent replaces the mechanical/experimental trial-and-error process with computational prediction and analysis. Instead of physically testing multiple primer versions through repeated PCR experiments, the system uses bioinformatics tools and thermodynamic calculations to predict primer performance in silico, substituting computational mechanics for experimental iteration.
3Stability of the object's composition
If primer length is increased, then hybridization stability is improved, but primer-dimer formation increases
Solution Approach 1:
The patent resolves this contradiction by optimizing primer length to a specific range (18-25 nucleotides) that provides sufficient hybridization stability while limiting the opportunity for self-complementarity. This precise parameter optimization balances the competing requirements of stability and dimer prevention.
Solution Approach 2:
The patent employs feedback mechanisms by calculating thermodynamic parameters (ΔG values) for both target hybridization and primer self-interactions. The design process uses this feedback information to select primers where the free energy of target binding is significantly more favorable than self-dimer formation, ensuring specific amplification while maintaining stability.
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 significantly reduces primer-homodimer and hairpin formation, enabling high-yield production of DNA templates, ensuring effective DNA synthesis.
Implementation Method 1
a set of primers bind to the DNA template fragment via Watson-Crick base pairing
Implementation Method 2
direct elongation toward opposite ends of the target sequence being amplified
Data Source
AI summary
The present disclosure generally relates to the use of linear nucleic acid primers for the amplification of a target nucleic acid sequence, for example, in a cell-free environment. In some embodiments, compositions of the linear nucleic acid primers are provided. For example, in some embodiments, the linear nucleic acid primers comprise a guanosine or a cytidine at 3′ terminal end. In some embodiments, the linear nucleic acid primers have been optimized to prevent primer-homodimer and/or hairpin formation and to exclude cumbersome codon sequences. In some embodiments, methods are provided for the amplification of a DNA template fragment using the linear nucleic acid primers. Thus, in some cases, the use of the nucleic acid primers, as described herein, may allow for the reduction in amplification of non-specific hybridization events while allowing for the amplification of the target nucleic acid sequence.