LAMP Diagnostic Master Mix Using pH-Sensitive Dyes for Visual Detection
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Solution Overview
Problem
Current molecular diagnostic tests for infectious agents, such as the SARS-CoV-2 virus, face challenges with sensitivity and accuracy due to viral mutations, particularly the B.1.1.7 variant, which affects the TaqPath COVID-19 multiplex RT-qPCR test, and require expensive equipment and technical expertise, limiting their use in widespread epidemics.
Innovation Solution
A master mix comprising a DNA polymerase suitable for isothermal amplification, dNTPs, and a pH-sensitive or metallochromic dye that changes color or fluorescence in response to DNA amplification, allowing for visual detection without the need for expensive instrumentation, and optionally including reversible inhibitors and multiple primer sets for enhanced sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RT-qPCR is used for diagnostic testing, then detection sensitivity and accuracy are improved, but device complexity and cost increase due to requirement for expensive laboratory instruments
Solution Approach 1:
The patent replaces complex mechanical/optical detection systems (qPCR instruments) with a simple colorimetric detection system. The LAMP reaction uses pH-sensitive dyes that change color in response to amplification, eliminating the need for expensive fluorescence detectors and thermal cyclers, while maintaining high detection sensitivity through isothermal amplification
Solution Approach 2:
The patent changes the detection parameter from fluorescence intensity (requiring expensive instruments) to pH-induced color change (detectable by eye or simple devices). By using pH-sensitive dyes that respond to the acidification caused by LAMP amplification, the system achieves sensitive detection without complex instrumentation
2Measurement precision
If TaqPath RT-qPCR test is used, then diagnostic accuracy is improved, but adaptability decreases due to failure to detect viral variants with mutations in primer binding regions
Solution Approach 1:
The patent segments the diagnostic approach by using multiple primer sets targeting different regions of the viral genome. This allows the LAMP assay to detect variants even when one target region has mutations, as other primer sets can still bind and initiate amplification, thereby maintaining diagnostic accuracy across different viral strains
Solution Approach 2:
The patent creates a universal LAMP primer set design that can detect multiple viral variants simultaneously. By targeting conserved regions and using degenerate primers, the assay maintains functionality across different SARS-CoV-2 variants, including alpha, beta, and gamma variants, without requiring redesign
3Ease of operation
If molecular diagnostic tests are made simple for widespread use, then ease of operation is improved, but measurement precision may deteriorate due to simplified detection methods
Solution Approach 1:
The patent uses pH-sensitive dyes that undergo distinct color changes (e.g., from red to yellow) in response to LAMP amplification. This visual colorimetric response provides clear, unambiguous results that are easy to interpret while maintaining high detection sensitivity, bridging the gap between simplicity 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
Enables rapid, specific, and sensitive detection of SARS-CoV-2 and other pathogens in clinical and environmental samples, reducing the impact of viral mutations and eliminating the need for sophisticated laboratory equipment, facilitating broader surveillance and control efforts.
Implementation Method 1
A master mix comprising a DNA polymerase suitable for isothermal amplification, dNTPs, and a pH-sensitive or metallochromic dye that changes color or fluorescence in response to DNA amplification
Implementation Method 2
A master mix comprising a DNA polymerase suitable for isothermal amplification, dNTPs, and a pH-sensitive or metallochromic dye that changes color or fluorescence in response to DNA amplification
Implementation Method 3
A master mix comprising a DNA polymerase suitable for isothermal amplification of DNA
Data Source
AI summary
Kits and methods are described that are directed to specific and sensitive methods of target nucleic acid detection and more specifically detecting target nucleic acids directly from biological samples. The kits and methods were developed to be easy to use involving a minimum number of steps and giving rapid and consistent results either at point of care or in high throughput situations. The kits and methods utilize in various combinations, reversible inhibitors of kit components, thermolabile enzymes, poloxamers, various salts, indicators and one or more Loop-Mediated Isothermal Amplification (LAMP) primer sets for detecting single and/or multiple targets and variants of the targets including SARS-CoV-2 targets and variants thereof in a single reaction. The kits and methods permit detection of the target nucleic with similar sensitivity regardless of the presence of undefined mutations that may enhance the virulence of cells or viruses containing the undefined mutations.