Thiolated ssDNA Enhances PCR Specificity via Intermediary Binding
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Solution Overview
Problem
Polymerase Chain Reaction (PCR) often experiences non-specific amplification due to interference from side reactions like primer dimers, leading to low efficiency or failure, despite optimization efforts with additives like DMSO and nano-metals, which can inhibit polymerase activity.
Innovation Solution
Incorporating thiolated single-stranded DNA into the PCR system, specifically oligonucleotides with a thiolalkyl group at the 5′ or 3′ end and a Tm value of at least 37.7° C., which are non-complementary to the target sequence, to enhance specificity without inhibiting polymerase activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PCR amplification is performed without additives, then the amplification process is simple, but non-specific amplification occurs seriously reducing efficiency
Solution Approach 1:
Thiolated single-stranded DNA acts as an intermediary substance in the PCR reaction system. It binds to the template DNA and facilitates specific primer annealing, thereby improving amplification specificity without requiring complex additive mixtures. The thiolated ssDNA mediates between the template and primers, ensuring accurate target amplification.
Solution Approach 2:
The invention changes the chemical parameter of the PCR system by introducing thiolated single-stranded DNA with specific properties (Tm value ≥37.7°C, non-complementary to target sequence). This parameter change improves the thermodynamic conditions of the reaction, enhancing specificity while maintaining simplicity.
2Reliability
If DMSO, glycerine, betaine, or nano-metals are added to improve specificity, then non-specific amplification is reduced to some degree, but the reaction system becomes more complex and polymerase activity may be inhibited
Solution Approach 1:
The invention extracts the essential function of PCR additives (improving specificity) and implements it through a single, well-defined component: thiolated single-stranded DNA. This eliminates the need for multiple different additives (DMSO, glycerine, betaine, nano-metals), simplifying the reaction system while maintaining improved specificity.
Solution Approach 2:
Thiolated single-stranded DNA performs multiple functions simultaneously: it improves amplification specificity, maintains polymerase activity, and works across different PCR conditions. This universal component replaces the need for multiple specialized additives, reducing system complexity.
3Reliability
If excessive nano-metals are added to reduce non-specific amplification, then specificity improves, but polymerase activity is inhibited reducing amplification efficiency
Solution Approach 1:
Thiolated single-stranded DNA serves as a temporary, consumable component in the PCR reaction that performs its specificity-enhancing function without the side effects of nano-metals. It is designed to be present only during the amplification process and does not accumulate to inhibit polymerase activity like excessive nano-metals would.
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 addition of thiolated single-stranded DNA significantly reduces non-specific amplification, improving the specificity and efficiency of PCR amplification, with ease of preparation, wide applicability, and low cost, while maintaining stability and usability.
Implementation Method 1
it has been proved that more stable hydrogen bonding can occur between hydroxy nucleobases or thiol nucleobases and nucleobases in the target nucleic acid
Data Source
AI summary
An application of thiolated single-stranded DNA enhances specific amplification of polymerase chain reaction, namely a method for enhancing specific amplification of polymerase chain reaction by utilizing thiolated single-stranded DNA, which includes the following step: adding an appropriate amount of the thiolated single-stranded DNA into a PCR system to perform PCR amplification, wherein the appropriate amount means that the final concentration of the thiolated single-stranded DNA in a 20 μL reaction system is not less than 15 μM. The thiolated single-stranded DNA meets the following conditions: the thiolated single-stranded DNA is one segment of any sequence which is non-complementary and non-homologous to a target sequence; the Tm value is not less than 37.7° C.; and at least one end contains a thiolalkyl group SH—C6H12—.