Multiplex PCR Primer Library to Minimize Non-Target Amplicons
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Solution Overview
Problem
Current multiplex PCR methods suffer from the formation of non-target amplification products, such as primer dimers, which limit the use of amplified products for further analysis, especially in applications like Non-Invasive Prenatal Genetic Diagnosis (NPD), where improved sensitivity and specificity are needed to reduce time and cost.
Innovation Solution
A method involving a library of non-immobilized primers that simultaneously hybridize to multiple target loci, using optimized annealing temperatures and conditions to minimize dimer formation, followed by primer extension and sequencing to produce target amplicons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple oligonucleotide primers are combined in the same PCR reaction to amplify multiple target nucleic acids simultaneously, then assay throughput is increased and experimental procedures are simplified, but non-target amplification products such as primer dimers are generated which limit the use of amplified products for further analysis
Solution Approach 1:
The invention divides the multiplex PCR process into two separate stages: (1) a first PCR reaction that amplifies multiple target nucleic acids simultaneously using multiple primer pairs, and (2) a second PCR reaction that uses a single universal primer pair to amplify the first amplicons. This segmentation allows the first reaction to generate diverse targets while the second reaction produces uniform amplicons suitable for sequencing, thereby resolving the contradiction between high throughput and minimal non-target products.
Solution Approach 2:
The first amplicons serve as an intermediary between the multiple specific primers in the first PCR and the single universal primer in the second PCR. These intermediary amplicons contain universal binding sites that allow them to be amplified in the second reaction, enabling the conversion of diverse specific amplicons into a uniform format suitable for downstream analysis while preventing direct interaction between different specific primers that would generate non-target products.
2Adaptability or versatility
If the number of primers in multiplex PCR is increased to amplify more targets, then more nucleic acid regions can be analyzed in one reaction, but the risk of generating non-target amplicons increases significantly
Solution Approach 1:
The invention segments the amplification process into two distinct PCR reactions with different primer configurations. The first reaction can accommodate many specific primer pairs (high adaptability) to amplify multiple target loci, while the second reaction uses a single universal primer pair (high reliability) to amplify the first amplicons. This segmentation allows the system to achieve both high versatility in target coverage and high specificity in the final amplicon production.
Solution Approach 2:
The first amplicons act as an intermediary that decouples the specificity requirements of the first PCR from the second PCR. The first amplicons are designed with universal binding sites that enable them to serve as templates for the second universal primer pair, thereby ensuring that regardless of how many different specific primers are used in the first reaction, the second reaction will only produce specific amplicons from the intended targets, maintaining high reliability.
3Loss of time
If standard multiplex PCR methods are used to amplify multiple targets, then time and cost are reduced compared to sequential amplification, but the amplified products are limited for further analysis due to non-target products
Solution Approach 1:
The invention segments the amplification workflow into two sequential but optimized stages: first, a multiplex PCR that rapidly amplifies multiple targets to reduce time loss, and second, a universal PCR that produces clean, specific amplicons suitable for downstream applications. This segmentation maintains the time efficiency of multiplexing while ensuring the amplified products are of high quality and usability for further analysis such as sequencing.
Solution Approach 2:
The first amplicons serve as an intermediary product that bridges the rapid but imperfect first PCR and the quality-assured second PCR. These intermediary amplicons are designed to be efficiently generated in the first reaction (maintaining speed) while also being perfectly suited as templates for the second universal primer pair (ensuring usability). This intermediary step preserves the time benefits of multiplexing while guaranteeing product quality for downstream applications.
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 significantly reduces non-target amplification products, enabling efficient and accurate simultaneous amplification of multiple nucleic acid regions, enhancing the sensitivity and specificity of NPD and other applications.
Implementation Method 1
a library of test primers that simultaneously hybridize to at least 25 different target loci
Implementation Method 2
subjecting the reaction mixture to primer extension reaction conditions to produce amplified products
Data Source
AI summary
The invention provides methods for simultaneously amplifying multiple nucleic acid regions of interest in one reaction volume as well as methods for selecting a library of primers for use in such amplification methods. The invention also provides library of primers with desirable characteristics, such as minimal formation of amplified primer dimers or other non-target amplicons.