Nanoprobe-Based Genetic Testing for Point-of-Care Mutation Detection
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Solution Overview
Problem
Current genetic testing platforms for personalized medicine, such as those used for warfarin dosing, are costly and not suitable for point-of-care applications due to the need for expensive instruments and reagents, and they struggle with sensitive detection of mutations in heterogeneous samples like tumor DNA, where the mutant allele ratio is low.
Innovation Solution
A dual-nanoprobe assay using asymmetric PCR and colorimetric signals that employs two conjugates with phosphorodiamidate morpholino oligonucleotide analogs covalently coupled to nanoparticles, allowing for the detection of single-nucleotide polymorphisms without a control DNA template, and can be performed with a standard thermal cycler, reducing equipment and reagent costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current genetic testing platforms (DNA microarray, real-time PCR, single-base extension) are used, then genotyping can be performed, but the cost of instruments and reagents is high, making them unsuitable for point-of-care applications
Solution Approach 1:
The patent uses disposable nanoparticle-based probes with simple colorimetric readout instead of expensive, reusable instruments. The nanoparticle probes are single-use reagents that provide accurate genotyping through color changes, eliminating the need for costly real-time PCR instruments and complex reagent systems while maintaining measurement precision.
Solution Approach 2:
The patent employs colorimetric detection using nanoparticle probes that change color based on hybridization state. This simple optical readout replaces complex instrument-based detection systems, reducing device complexity while maintaining genotyping accuracy through visual or spectrophotometric color measurement.
2Ease of manufacture
If conventional genotyping methods are used, then standard protocols are available, but they require expensive instruments and cannot be performed at point-of-care settings
Solution Approach 1:
The nanoparticle probes are designed as simple, disposable reagents that can be stored at room temperature and used directly in standard thermal cyclers. This eliminates the need for specialized instruments and complex protocols, making the testing accessible at point-of-care settings while maintaining ease of manufacture through standard biochemical procedures.
Solution Approach 2:
The nanoparticle probes self-assemble with target DNA through hybridization and automatically generate colorimetric signals without requiring complex instrument control or specialized operational procedures. This self-service capability allows standard thermal cyclers to perform the genotyping without specialized training or equipment, improving point-of-care accessibility.
3Measurement precision
If standard nanoprobe assays are used for mutation detection, then the detection limit is approximately 1 nM, but genes cannot be analyzed directly and PCR amplification is necessary
Solution Approach 1:
The patent performs PCR amplification as a preliminary step to enrich target DNA sequences before nanoprobe hybridization. This preliminary action increases the concentration of target genes to levels detectable by the nanoprobe assay, achieving measurement precision below 1 nM while using standard PCR equipment rather than requiring direct analysis of low-abundance targets.
4Ease of operation
If a single nanoprobe assay is used for genotyping, then the procedure is simple, but unambiguous genotype determination cannot be achieved
Solution Approach 1:
The patent segments the genotyping assay into multiple parallel reactions, each using a different nanoprobe with distinct colorimetric signals. By running multiple segmented assays simultaneously in standard thermal cyclers, the system achieves unambiguous genotype determination through pattern recognition of color changes while maintaining procedural simplicity through standardized protocols.
Solution Approach 2:
The patent uses multiple nanoprobe conjugates that produce different color changes upon hybridization with their respective targets. This multi-color readout system enables unambiguous genotype determination by comparing the pattern of color changes across multiple probes, maintaining ease of operation through simple visual or spectrophotometric detection.
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 provides a robust, cost-effective genetic testing platform capable of unambiguous genotype determination with high sensitivity, suitable for point-of-care use, and can analyze samples with low mutant allele ratios, improving the efficiency of personalized medicine applications.
Implementation Method 1
the first oligonucleotide analog comprises a base sequence that is complementary to the unmutated sequence of the target nucleic acid, under conditions which allow the first conjugate and the target nucleic acid molecule to hybridize to each other
Implementation Method 2
determining the melting temperatures Tm of the complexes formed in the separate aliquots of the sample in steps (i) and (ii)
Data Source
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AI summary
The present application relates to methods of detecting a mutation in a target nucleic acid molecule. Two phosphorodiamidate morpholino oligomer probes that differ by at least one base are each covalently coupled to a nanoparticle and hybridised to a target sequence. The melting temperature of the complexes between each of the two probes and the target nucleic acid are measured and compared to determine whether the sample contains a nucleic acid with the mutation. Further, the present invention relates to kits comprising a first and second conjugate as described herein and to the use of such kits for the detection of mutations in a target nucleic acid molecule or for assigning a genotype to a target nucleic acid molecule.