Isothermal SNP Detection via Allele-Specific Blocking Primers
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Solution Overview
Problem
Current methods for detecting single nucleotide polymorphisms (SNPs) linked to drug resistance in infectious pathogens are hindered by high costs and time requirements, limiting their use outside specialized laboratories and preventing widespread deployment for point-of-care diagnostics.
Innovation Solution
The development of SNP-based loop-mediated isothermal amplification (sbLAMP) using six primers, including two for allele-specific amplification and universal self-stabilizing (USS) primers that prevent unspecific amplification, allowing for rapid and specific SNP detection under isothermal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-throughput methods such as Next Generation Sequencing or Sanger sequencing are used for SNP detection, then detection accuracy is improved, but cost and time to report results increase significantly
Solution Approach 1:
The patent replaces the thermal cycling mechanism of PCR-based methods with isothermal amplification, eliminating the need for repeated heating and cooling cycles. This substitution of the amplification mechanism enables rapid SNP detection within 35 minutes while maintaining high accuracy, directly resolving the contradiction between detection precision and time consumption.
Solution Approach 2:
The patent changes the temperature parameter from variable (thermal cycling) to constant (isothermal conditions), simplifying the reaction conditions and reducing the time required for amplification. This parameter change enables faster result reporting while preserving detection accuracy through optimized primer designs and reaction conditions.
2Measurement precision
If PCR-based methods are used for SNP detection, then detection sensitivity is improved, but device complexity and cost increase due to requirement of thermal cycling and electrophoresis
Solution Approach 1:
The patent replaces complex thermal cycling equipment with simple isothermal incubation devices, eliminating the need for programmable thermal cyclers and electrophoresis systems. This substitution maintains detection sensitivity while dramatically reducing device complexity, making the technology suitable for point-of-care applications in resource-limited settings.
Solution Approach 2:
The patent extracts and eliminates unnecessary components from the PCR workflow, such as thermal cycling control systems and electrophoresis apparatus, by using isothermal amplification that requires only constant temperature incubation. This extraction of essential components simplifies the overall system while preserving analytical sensitivity.
3Measurement precision
If allele-specific PCR techniques are used for SNP detection, then detection specificity is improved, but time and cost per sample increase due to multiple primers and validation steps
Solution Approach 1:
The patent merges multiple primer functions into a single isothermal amplification reaction, combining allele-specific primers with blocking primers and universal primers in one reaction system. This consolidation eliminates the need for separate validation steps and reduces the time per sample while maintaining high specificity through the cooperative action of multiple primers targeting different regions of the gene.
Solution Approach 2:
The patent designs universal primer sets that can detect multiple SNPs and allele types in a single reaction, making the assay multi-functional and applicable to various pathogen panels. This universality reduces the time and cost per sample by eliminating the need for separate reactions for different SNP detections, while maintaining specificity through carefully designed primer sequences.
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 method achieves high sensitivity, specificity, and rapid time-to-positive results (< 35 minutes) for SNP detection, making it suitable for limited-resource settings and enabling rapid SNP screening for infectious diseases.
Implementation Method 1
amplifying under isothermal conditions and stringent conditions a nucleic acid sequence from a sample, in a reaction mixture comprising (i) the nucleic acid sequence, (ii) a nucleic acid polymerase, (iii) a nucleoside triphosphate mixture
Implementation Method 2
a forward inner primer targeting the first allele (FIPa1), comprising a F1c region which anneals to a F1 region of the nucleic acid sequence in the presence of the first allele
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3E
AI summary
The present application relates to methods for detecting a first allele of a single nucleotide polymorphism (SNP) in a nucleic acid sequence under isothermal conditions using primers specific for said first allele, in particular using Loop mediated isothermal amplification (LAMP), wherein the amplification of a second allele is prevented by using blocking primers.