Filtration Method for Microbial Contamination Detection
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Solution Overview
Problem
Current methods for detecting bacterial contamination in environmental samples are often slow, unreliable, and require cultivation steps, which limit their sensitivity and robustness, especially for detecting low concentrations of microorganisms.
Innovation Solution
A method that uses filtration to concentrate microorganisms without a cultivation step, employing a disposable closed filtration unit and a substrate that produces a detectable moiety upon interaction with contaminants, allowing for rapid and sensitive detection of even low concentrations of bacteria, including those as low as 1 bacterium/ml.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cultivation steps are used to increase sensitivity of detection, then detection sensitivity is improved, but detection time increases significantly (6-72 hours)
Solution Approach 1:
The method performs concentration of microorganisms through filtration before the detection step, preparing the sample in advance to enable direct detection without subsequent cultivation. This preliminary concentration action allows the detection to start immediately with enriched samples, resolving the time-sensitivity contradiction.
Solution Approach 2:
The invention extracts and removes the cultivation step from the traditional detection workflow by using filtration to concentrate microorganisms directly into a detectable state. By taking out the time-consuming cultivation phase and replacing it with physical concentration, the method achieves both high sensitivity and rapid detection.
2Measurement precision
If cultivation steps are performed to increase microbial concentration, then detection sensitivity is improved, but reliability decreases due to interference from sample compounds
Solution Approach 1:
The filtration step extracts and concentrates microorganisms while leaving interfering sample compounds in the filtrate. This separation action removes the harmful interference from the detection phase, improving both reliability and sensitivity simultaneously.
Solution Approach 2:
The filter acts as an intermediary that selectively retains microorganisms while allowing interfering compounds to pass through. This mediator enables the separation of target analytes from interfering substances, resolving the contradiction between sensitivity and robustness.
3Speed
If ATP detection by chemiluminescence is used for rapid detection, then detection speed is improved, but robustness decreases due to ubiquitous ATP and complex kinetics
Solution Approach 1:
The filtration step extracts and concentrates microorganisms while removing free ATP and other interfering substances from the sample matrix. By taking out the ubiquitous ATP that causes interference, the method enables use of chemiluminescence detection without sacrificing robustness, thus achieving both speed and reliability.
4Reliability
If enzyme activity detection is used for bacterial detection, then robustness is improved, but detection sensitivity decreases for low concentration samples
Solution Approach 1:
The filtration step performs preliminary concentration of microorganisms before enzyme activity detection. By concentrating the bacteria onto the filter membrane in advance, the method enhances the signal from low-concentration samples, enabling sensitive detection while maintaining the robustness of enzyme activity measurement.
Solution Approach 2:
The method combines physical concentration (filtration) with biochemical detection (enzyme activity). This composite approach integrates the sensitivity enhancement of physical concentration with the robustness of enzymatic reactions, achieving both high sensitivity and reliability.
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 significantly reduces detection time, eliminates interference from sample compounds, and provides a robust, reliable method for detecting microorganisms in various samples, including liquids, air, and surfaces, with high sensitivity and precision.
Implementation Method 1
passing a known volume of said medium through a filter from an influent side to an effluent side thereby concentrating the contaminants on the influent side of the filter
Implementation Method 2
contacting the influent side of the filter with a liquid vehicle containing at least one substrate that through interaction with the contaminants each produces a detectable moiety
Implementation Method 3
monitoring of the fluorescence derived from the released umbelliferone
Data Source
AI summary
Disclosed is a convenent sample preparation method for a medium suspected of containing contaminants, the method comprising a) passing a known volume of said medium through a filter from an influent side to an effluent side thereby concentrating the contaminants on the influent side of the filter, b) contacting the influent side of the filter with a liquid vehicle containing at least one substrate that through interaction with the contaminants each produces a detectable moiety, c) and allowing the substrate to interact with the contaminants on the influent side of the filter for a period of time, which is sufficient to allow the detectable moiety to be detected in the liquid vehicle. The method may further comprise a detection step, where the amount of detectable is determined in the liquid vehicle, preferably after the liquid vehicle has been separated from the contaminant, e.g. by passing the liquid vehicle through the filter and performing a measurement on the contaminant free liquid vehicle. Also disclosed is a kit for exercising the inventive method.