Rapid Pathogen Detection via Pre-Enrichment and Electrochemical Sensing
Solution Overview
Problem
Current pathogen detection methods in food and water supplies are slow and lack sensitivity, specificity, and rapidity, requiring several days to complete, which hinders early and effective prevention of outbreaks.
Innovation Solution
A method involving a pre-enrichment step with a liquid medium containing peptone, malachite green, and nonylphenol ethoxylate, followed by an enrichment step with ferric ammonium citrate, and subsequent purification using immunomagnetic particles and electrochemical sensor-based detection, allowing for the rapid detection of Salmonella within 8-30 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional pathogen detection methods are used, then sensitivity and specificity are maintained, but detection time is extended to several days
Solution Approach 1:
The patent applies preliminary action by performing pre-enrichment culture for 14-16 hours before the main detection procedure. This preliminary step increases the initial pathogen load in the sample, enabling faster detection in the subsequent enrichment and detection phases while maintaining sensitivity. The pre-enrichment medium contains selective agents that begin suppressing non-target organisms early in the process.
Solution Approach 2:
The patent employs parameter changes by optimizing incubation temperatures (37°C for pre-enrichment, then 42°C for enrichment), adjusting pH levels in enrichment media, and modifying nutrient compositions. These parameter optimizations create conditions that accelerate Salmonella growth rates while maintaining detection sensitivity, reducing the overall detection time from several days to approximately 30 hours.
2Measurement precision
If enrichment time is extended to improve detection sensitivity, then pathogen concentration increases, but detection time increases proportionally
Solution Approach 1:
The patent applies local quality by creating different enrichment conditions for different phases of detection. The pre-enrichment medium (Buffered Peptone Water with selective agents) differs from the main enrichment medium (Rappaport-Vassiliadis or Bolton broth). Each medium is locally optimized for specific functions: pre-enrichment recovers stressed pathogens and begins selective suppression, while main enrichment maximizes pathogen multiplication. This localized optimization enables faster overall detection while maintaining sensitivity.
Solution Approach 2:
The patent employs dynamics by implementing a two-stage enrichment process with different temperatures, media compositions, and durations. The system transitions from 37°C pre-enrichment for 14-16 hours to 42°C enrichment for additional hours. This dynamic approach allows the detection system to adapt to varying pathogen states and growth requirements, achieving both sensitivity and speed that a static single-stage process cannot provide.
3Measurement precision
If selective pressure is increased to improve specificity, then non-target organisms are suppressed, but pathogen growth may be inhibited
Solution Approach 1:
The patent applies preliminary action by introducing selective agents gradually through the pre-enrichment phase. Rather than applying full selective pressure immediately, the system first uses buffered peptone water with mild selective agents for 14-16 hours to recover pathogens and begin suppressing contaminants. This gradual introduction of selective pressure allows pathogens to adapt and grow while maintaining specificity, avoiding the growth inhibition that would result from immediate high-level selective pressure.
Solution Approach 2:
The patent employs dynamics by adjusting selective pressure levels across different enrichment phases. The pre-enrichment medium contains lower concentrations of selective agents compared to the main enrichment medium. This dynamic adjustment of selective pressure enables the system to balance specificity and pathogen growth rate, allowing sufficient pathogen multiplication while progressively suppressing non-target organisms throughout the detection process.
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 method enhances sensitivity and specificity while reducing detection time, enabling quicker identification of pathogens and potentially preventing widespread illness.
Implementation Method 1
purifying the liquid enrichment medium to increase the concentration of the Salmonella and decrease contaminants using an immuno-precipitation method employing antibodies for the Salmonella linked to magnetic particle
Implementation Method 2
detecting the presence or absence of Salmonella by analyzing an aliquot of the purified enrichment medium from step (c), using an electrochemical sensor-based detection method
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
The present specification discloses methods of detecting a pathogen of interest and components useful in carrying out these methods, including a pre-enrichment media, and enrichment media and a detection solution.