Oligocation-Conjugated Primers for Isothermal DNA Amplification
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Solution Overview
Problem
Current DNA amplification methods, such as whole-genome amplification, face challenges when dealing with trace amounts of target DNA, resulting in incomplete amplification, sequence coverage dropout, and amplification bias, especially when amplifying DNA from single cells or small quantities, due to inefficient primer hybridization and generation of undesirable chimeric products.
Innovation Solution
The use of oligocation-oligonucleotide conjugate primers, where an oligocation moiety is covalently conjugated to the 5′ end of an oligonucleotide sequence, enhances target recognition and hybridization efficiency, allowing for more stringent hybridization conditions and reducing electrostatic repulsion, thereby improving the amplification of trace DNA amounts through isothermal amplification reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional DNA amplification methods are used with trace amounts of target DNA, then amplification can be performed, but incomplete amplification and sequence coverage dropout occur
Solution Approach 1:
The patent modifies the chemical parameters of the primer by conjugating oligocation moieties (such as spermine, polylysine, or polyarginine) to the 5' end of the oligonucleotide sequence. This parameter change alters the electrostatic properties of the primer, enabling it to effectively bind to trace amounts of target DNA and improve amplification completeness and sequence coverage.
2Productivity
If conventional PCR or isothermal amplification is used, then DNA amplification can be achieved, but amplification bias and chimeric product formation occur
Solution Approach 1:
The patent creates a composite primer structure by conjugating oligocation moieties (such as spermine, polylysine, or polyarginine) to the 5' end of the oligonucleotide sequence. This composite structure combines the DNA-binding capability of the oligonucleotide with the electrostatic attraction properties of the oligocation, improving amplification specificity and reducing chimeric product formation.
3Quantity of substance
If standard primers are used for hybridization, then amplification can proceed, but hybridization efficiency is insufficient for trace DNA
Solution Approach 1:
The patent uses oligocation moieties (such as spermine, polylysine, or polyarginine) conjugated to the 5' end of the primer to counteract the electrostatic repulsion between the negatively charged phosphate backbone of the primer and the target DNA. This counterweight effect enhances hybridization kinetics and efficiency, enabling effective binding even at trace DNA concentrations.
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 increases the sensitivity and kinetics of DNA amplification, providing more balanced and complete sequence coverage, even from single cells, while minimizing chimeric product formation, by maintaining primer structure compatibility with DNA polymerase activity and reducing amplification bias.
Implementation Method 1
reducing electrostatic repulsion
Implementation Method 2
The complementary strand is assembled from deoxynucleoside triphosphates (dNTPs) by a DNA polymerase. The complementary strand synthesis proceeds in 5′→3′ direction starting from the 3′ terminal end of a primer sequence
Implementation Method 3
amplifying at least one portion of the target DNA using the DNA amplification reaction mixture to produce at least one amplicon
Data Source
AI summary
Provided herein are methods and kits for isothermal nucleic acid amplifications that use an oligocation-oligonucleotide conjugate primer for amplifying a target nucleic acid to generate amplicons. Isothermal DNA amplification methods that employ a strand displacing DNA polymerase and polyamine-oligonucleotide conjugate primer are also provided.