Multiplex Digital PCR Pathogen Detection in Environmental Water
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Solution Overview
Problem
Current methods for detecting pathogens in environmental water matrices, such as those used for SARS-CoV-2 in wastewater, require sample purification steps that can lead to loss of genetic material and reduced sensitivity, limiting the detection of low pathogen concentrations.
Innovation Solution
A method utilizing multiplex digital PCR (dPCR) that omits initial sample purification, allowing direct amplification of pathogen sequences from unpurified environmental water samples, thereby enhancing sensitivity and enabling detection of lower concentrations of pathogens like SARS-CoV-2 without significant loss of nucleic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sample purification steps are performed before pathogen detection, then interference from environmental water matrix is reduced, but genetic material is lost and sensitivity decreases
Solution Approach 1:
The invention extracts only the necessary pathogen nucleic acid from the complex environmental water matrix using specific primers and probes, leaving behind the interfering matrix components. This selective extraction approach maintains detection accuracy while minimizing nucleic acid loss compared to comprehensive purification methods.
Solution Approach 2:
The invention changes the detection parameter from requiring purified sample to accepting unpurified sample directly. By optimizing the dPCR assay conditions and using multiplex digital PCR, the method achieves reliable detection without the need for traditional purification steps, thereby preventing nucleic acid loss.
2Measurement precision
If traditional PCR methods are used with purification steps, then false positives are reduced, but detection sensitivity for low pathogen concentrations is limited
Solution Approach 1:
The invention segments the detection process into multiple independent digital PCR reactions, each targeting specific pathogen sequences. This segmentation allows for highly sensitive detection of low pathogen concentrations while maintaining assay reliability through replicate measurements and statistical analysis of partition data.
Solution Approach 2:
The invention uses digital PCR as an intermediary method between traditional PCR and direct detection. The dPCR process partitions the sample into numerous small reactions, enabling sensitive detection of low pathogen concentrations while the multiplex approach maintains assay efficiency by detecting multiple targets simultaneously.
3Object-affected harmful factors
If sample purification is performed, then PCR inhibitors are removed, but detection of low pathogen concentrations below 200 copies/L becomes difficult
Solution Approach 1:
The invention replaces the mechanical purification system with a molecular-based detection system. By using highly specific primers and probes in a digital PCR assay, the method can distinguish true pathogen signals from background interference without requiring physical removal of inhibitors, thereby achieving detection limits below 200 copies/L.
Solution Approach 2:
The invention performs preliminary optimization of the dPCR assay conditions, including primer and probe design, to ensure high specificity and sensitivity. This preliminary action allows the assay to function effectively in unpurified samples by preventing false positives and maintaining detection capability at low pathogen concentrations.
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 allows for the detection of as low as 200 copies/L of SARS-CoV-2, significantly improving sensitivity compared to traditional methods, and can identify infected individuals within a larger population, such as 100,000 persons, rather than just 2,000, by maintaining high nucleic acid recovery and assay efficiency.
Implementation Method 1
Techniques such as the Polymerase Chain Reaction (PCR) allow direct detection of the pathogen genetic material
Implementation Method 2
the presence of SARS-CoV-2 in sewage was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR)
Data Source
AI summary
Methods, reagents and a kit for the detection of a pathogen in a test sample, notably a sample of an environmental water matrix. The method involves the detection by multiplex digital PCR (dPCR) of several pathogen sequences without prior purification of the sample. Also, a method for detection of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus in a sample, notably sample of an environmental water matrix.