TR-LAMP Tandem Repeat Detection for Azole-Resistant Aspergillus
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Solution Overview
Problem
Current diagnostic methods for detecting azole-resistant Aspergillus fumigatus infections, such as culture, microscopy, and antibody-based tests, are time-consuming and lack specificity, while PCR-based methods require laboratory equipment and skilled personnel, necessitating a simple, rapid, and accurate diagnostic for both clinical and field settings.
Innovation Solution
A modified loop-mediated isothermal amplification (LAMP) assay, termed TR-LAMP, is developed to detect tandem repeats, particularly targeting the TR34/L98H allele in the cyp51A gene, using specific primers for rapid and sensitive detection of azole-resistant A. fumigatus, compatible with point-of-care platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR-based molecular methods are used for detecting azole-resistant alleles, then sensitivity and specificity are improved, but device complexity and operational difficulty increase due to requiring laboratory equipment and experienced personnel
Solution Approach 1:
The patent replaces complex PCR-based molecular methods with a visual detection system based on colorimetric changes. The detection system uses a test strip with detection zones that change color in response to the presence of tandem repeats, eliminating the need for sophisticated laboratory equipment like thermal cyclers and PCR machines. This substitution maintains high detection precision while dramatically simplifying the device requirements and operational complexity.
Solution Approach 2:
The patent changes the detection parameter from molecular amplification signals to colorimetric responses. By using antibodies conjugated to colorimetric indicators that bind to tandem repeats, the system transforms the detection mechanism into a visual color change that can be observed with the naked eye or simple imaging devices, thereby reducing equipment complexity while preserving detection accuracy.
2Device complexity
If conventional diagnostic methods such as culture and microscopy are used, then device complexity is reduced, but productivity and speed of detection deteriorate due to requiring several days to observe the fungus
Solution Approach 1:
The patent employs pre-assembled test strips with all necessary reagents, antibodies, and detection zones prepared in advance. The tandem repeat-specific antibodies and colorimetric indicators are pre-conjugated and positioned on the strip, eliminating the need for complex sample processing and multi-step procedures during actual testing. This preliminary preparation enables rapid detection within minutes while keeping the device simple and equipment-free.
Solution Approach 2:
The detection system is segmented into distinct functional zones on the test strip, including sample application areas, detection zones with specific antibodies, and control zones. This segmentation allows parallel processing of multiple detection functions simultaneously, dramatically increasing productivity compared to sequential conventional methods while maintaining simplicity of the overall device.
3Productivity
If antibody-based tests are used for rapid detection, then productivity is improved, but measurement precision deteriorates because they cannot determine the occurrence of azole-resistance
Solution Approach 1:
The patent applies local quality by using different antibodies with specific binding affinities for different targets on the test strip. The tandem repeat-specific antibodies are positioned in specific detection zones to selectively detect azole-resistance markers, while other zones detect general fungal presence. This localized functional differentiation enables the system to simultaneously achieve rapid detection and precise identification of resistance alleles.
Solution Approach 2:
The test strip is designed with multi-functionality, capable of detecting both general fungal presence and specific azole-resistance markers in a single assay. By incorporating multiple antibody types and detection zones on one strip, the system universally addresses both rapid diagnosis and resistance detection needs, eliminating the need for separate tests while maintaining both speed and precision.
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
TR-LAMP provides high analytical sensitivity and specificity for detecting the TR34 mutation, enabling rapid diagnosis of invasive aspergillosis and facilitating point-of-care diagnostics through visual or smartphone-compatible detection.
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
wherein the FIP or BIP anneals to a target region comprising one or more nucleotides from each of two repeat units
Data Source
Figure 1(A)~1(D)
Figure 2
Figure 3
AI summary
The present application relates to methods for detecting a tandem repeat in a nucleic acid sequence under isothermal conditions using primers.