Simplified Polynucleotide Detection Using Circular Probe Constructs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing PCR-based methods for polynucleotide sequence detection face limitations such as false positives due to primer-primer interactions, limited multiplexing capability, difficulty in quantification, and sensitivity to genetic mutations, especially when targeting low-level analytes.
Innovation Solution
A method utilizing a single-stranded probe oligonucleotide with a 3' end complementary to the target sequence, a blocking oligonucleotide, a pyrophosphorolysing enzyme, and a ligase to create a partially digested strand and circular construct, followed by signal detection to infer the presence of the target sequence, enhancing specificity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PCR-based methods are used for polynucleotide sequence detection, then amplification of target DNA or RNA can be achieved, but false positive results occur due to unwanted amplification of other nucleic acid sequences
Solution Approach 1:
The probe is divided into multiple segments including a target-complementary region and a non-target region. The non-target region provides additional specificity by requiring binding to both target and non-target sequences, effectively segmenting the recognition process into multiple specific binding events rather than a single amplification step.
Solution Approach 2:
A blocking oligonucleotide acts as an intermediary element that binds to non-target sequences and prevents unwanted amplification. This intermediary component specifically blocks primer binding to non-target sequences, thereby eliminating false positives without affecting target amplification.
2Adaptability or versatility
If multiplexing of PCR-based methods is increased to detect more target sequences, then detection coverage is improved, but primer-primer interactions increase resulting in limited operational windows
Solution Approach 1:
The method extracts the amplification step from the detection specificity requirement. By using a probe-based approach where the probe itself serves as the amplification primer and contains the detection specificity elements, the system can multiplex more targets without increasing primer-primer interaction complexity.
Solution Approach 2:
The probe oligonucleotide serves multiple functions: it acts as the amplification primer, contains the target-specific recognition element, and includes the non-target region for enhanced specificity. This multi-functionality reduces the number of separate components needed for multiplexing.
3Reliability
If PCR reaction cycles exponentially to amplify target, then detection sensitivity is improved, but quantification of target becomes difficult due to small variations in reaction efficiency
Solution Approach 1:
The probe is pre-designed with a specific structure including a non-target region that extends beyond the amplification region. This preliminary structural configuration ensures that even with exponential amplification, the probe maintains its specificity and the amplification efficiency variations do not significantly impact quantification accuracy.
4Measurement precision
If PCR primers are designed to target specific genetic variants, then detection specificity is improved, but mutations in the targeted region cause false negatives or false positives
Solution Approach 1:
The probe is segmented into a target-complementary region and a non-target region. The non-target region provides a buffer zone that maintains probe stability even when mutations occur in the target region, segmenting the impact of mutations so they do not completely abolish binding.
Solution Approach 2:
The non-target region of the probe acts as a cushioning element that compensates for potential mutations in the target region. By extending the probe beyond the critical target sequence, the system is beforehand protected against mutation-induced binding failure.
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 method provides fast, efficient, and specific detection of target polynucleotides, even at low concentrations, with improved multiplexing capability and reduced false positives, suitable for applications in cancer, infectious disease, and transplant organ rejection diagnostics.
Implementation Method 1
A 0 is pyrophosphorolysed in the 3'-5' direction from the 3' end to create at least a partially digested strand A 1
Implementation Method 2
A 1 undergoes ligation using a splint to form A 2
Implementation Method 3
a blocking oligonucleotide complementary to a non-target polynucleotide sequence wherein the blocking oligonucleotide anneals to any non-target polynucleotide sequence present
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
Provided herein are methods for improved polynucleotide detection.