Isothermal DNA Amplification for Sensitive Analyte Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ligand binding assays, such as ELISA, face limitations in sensitivity due to background noise and unspecific binding, which hampers the detection of low-abundance biomarkers.
Innovation Solution
A method involving a ligand with a primer oligo-deoxyribonucleotide bound to a binding moiety, which undergoes reverse transcription with a template polyribonucleotide and labelled deoxyribonucleotide triphosphates, allowing for signal amplification without temperature cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional enzyme immunoassays are used, then the assay is simple to perform, but the detection sensitivity is limited to approximately 1 pg/ml due to background noise and unspecific binding
Solution Approach 1:
The patent introduces an oligonucleotide primer as an intermediary component that bridges the antibody-analyte complex and the DNA amplification system. The primer is covalently attached to the antibody and serves as a template for DNA synthesis, enabling signal amplification without requiring the antibody itself to be directly amplified. This intermediary approach resolves the contradiction by decoupling the binding function (antibody) from the amplification function (DNA primer), achieving high sensitivity while maintaining assay simplicity
Solution Approach 2:
The patent changes the detection parameter from direct enzyme activity measurement to amplified DNA signal detection. By incorporating an oligonucleotide primer that can be exponentially amplified through DNA polymerase reactions, the detection sensitivity is enhanced by several orders of magnitude. The parameter change from linear enzyme signal to exponential DNA amplification signal resolves the sensitivity limitation while the use of standard PCR equipment keeps the complexity manageable
2Measurement precision
If immuno-PCR methods are used to improve sensitivity, then detection sensitivity increases, but the assay requires temperature cycling and multiple complex steps
Solution Approach 1:
The patent extracts the temperature cycling step from the immunoassay protocol by using a isothermal DNA amplification method. Instead of requiring repeated heating and cooling cycles, the assay uses a single-temperature incubation with a engineered DNA polymerase that can synthesize DNA at constant temperature. This extraction of the temperature cycling requirement maintains the sensitivity benefits of immuno-PCR while dramatically reducing assay time and complexity
Solution Approach 2:
The patent performs preliminary covalent attachment of the oligonucleotide primer to the antibody before the binding assay. This pre-conjugation step ensures that only antibodies specific to the analyte carry the amplifiable primer, eliminating the need for subsequent temperature cycling to denature and separate components. The preliminary action of covalent bonding simplifies the overall protocol while maintaining high sensitivity
3Measurement precision
If signal amplification is increased to detect lower analyte concentrations, then detection sensitivity improves, but system background noise and unspecific binding also increase
Solution Approach 1:
The patent applies local quality by confining the DNA amplification reaction to only those locations where the analyte-specific antibody-primer complex is formed. The oligonucleotide primer is covalently attached to the antibody, ensuring that DNA synthesis occurs only at sites of specific antigen-antibody binding. This spatial localization of amplification prevents background noise generation from unspecific binding sites, resolving the contradiction between signal amplification and background reduction
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 enhances detection sensitivity by amplifying the signal while reducing background noise, enabling the detection of analytes at much lower concentrations without the complexity and time associated with traditional immuno-PCR methods.
Implementation Method 1
an enzyme with reverse transcriptase activity; incubating the bound first ligand comprising the attached primer oligo-deoxyribonucleotide, the template polyribonucleotide, the labelled deoxyribonucleotide triphosphates, and the enzyme under conditions suitable for synthesis of a labelled DNA-strand by said enzyme
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
The present invention relates to a method for detection of an analyte of interest in a sample comprising the use of a ligand capable of specific binding to the analyte, wherein the ligand comprises a primer oligo-deoxyribonucleotide having a length of 18-40 nucleotides, a template polyribonucleotide being longer than the primer oligo-deoxyribonucleotide and having a sequence that is at least partially complementary to the primer oligo-deoxyribonucleotide, a plurality of labelled deoxyribonucleotide triphosphates, and an enzyme with reverse transcriptase activity, wherein the analyte is detected by detecting any labelled DNA strand synthesized by the enzyme. The invention also relates to a kit comprising reagents for performing such a method.