Porous Membrane Microorganism Detection Device

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Solution Overview

Problem

Existing methods for monitoring microorganisms in industrial samples are limited in their ability to accurately enumerate microorganisms due to slow diffusion rates of metabolites, which are inconsistent across duplicate samples, and cannot be thermally sterilized, making them inadequate for both clinical and sterility tests.

Innovation Solution

An apparatus with a container having a growth zone and a detection zone separated by a porous membrane, allowing rapid diffusion of metabolic by-products while preventing microorganisms and particulate matter, utilizing a dye indicator that changes color in response to microbial growth, enabling optical monitoring of microorganism presence and activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid sensor with membrane is used to separate indicator substrate from growth media, then thermal sterilization capability is achieved, but diffusion rate of metabolites becomes slow and inconsistent

Engineering Contradiction:
Improvethermal sterilization capabilityVSAvoiddiffusion rate of metabolites
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent employs a porous membrane as the separating layer between the growth media and indicator substrate. The porous structure allows rapid diffusion of metabolic by-products while maintaining the solid-phase separation needed for thermal sterilization. This resolves the contradiction by providing both thermal stability and fast metabolite transport through the porous architecture.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The device combines liquid growth media containing indicator substrates with a solid porous membrane support. This composite structure integrates the advantages of both liquid phase (fast diffusion) and solid phase (thermal sterilization capability), resolving the contradiction between sterilization reliability and diffusion speed.

Inventive Principle:
Principle #40Composite materials

2Reliability

If indicator substrate is immobilized on solid membrane, then device can be thermally sterilized, but diffusion consistency across duplicate samples deteriorates

Engineering Contradiction:
Improvesterility test capabilityVSAvoidenumeration accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the physical state parameters of the system by using a porous membrane with controlled pore size and distribution. This parameter optimization allows consistent metabolite diffusion rates while maintaining thermal sterilization capability, thereby improving both sterility test reliability and enumeration precision.

Inventive Principle:
Principle #35Parameter changes

3Speed

If semi-liquid agar matrix is used for indicator substrate, then diffusion rate of metabolites increases, but thermal sterilization capability is lost

Engineering Contradiction:
Improvediffusion rate of metabolitesVSAvoidthermal sterilization capability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent uses a porous membrane structure that provides liquid-like diffusion pathways while maintaining solid-phase thermal stability. The porous architecture enables fast metabolite transport comparable to semi-liquid matrices while retaining the ability to withstand thermal sterilization processes.

Inventive Principle:
Principle #31Porous materials

4Reliability

If solid sensor separates indicator substrate from growth media, then interference from sample materials is prevented, but diffusion of metabolites becomes rate-limiting

Engineering Contradiction:
Improveresistance to interferenceVSAvoidenumeration speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The porous membrane provides effective separation between growth media and indicator substrate, preventing interference from sample materials while offering numerous diffusion pathways for metabolites. This maintains both interference resistance and enumeration speed by optimizing the porous structure.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The thin porous membrane film minimizes diffusion path length while maintaining separation functionality. This thin-film architecture reduces the diffusion barrier, enabling fast metabolite transport while preserving the protective separation that prevents interference.

Inventive Principle:
Principle #30Flexible shells and thin films

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 accurate enumeration of microorganisms, thermal sterilization capability, and effective antimicrobial susceptibility testing, with faster diffusion rates and consistent results, suitable for both presence/absence tests and enumeration evaluations.

Implementation Method 1

a separating layer comprising a membrane material interposed between said growth and detection zones, wherein the membrane is a porous material and wherein the membrane is configured to prevent microorganisms and particulate matter of the test sample from penetrating into the detection zone and to permit diffusion of molecules of metabolic by-products into the detection zone

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

utilizing a dye indicator that changes color in response to microbial growth

Methodology Applied
Scientific EffectColor change:

Implementation Method 3

enabling optical monitoring of microorganism presence and activity

Methodology Applied
Scientific EffectOptical detection:

Data Source

PatentEP2455455B1Optical method and device for detection and enumeration of microorganisms
Publication Date: 2013.12.18 EDEN GIDEON
  • EP2455455B1 patent drawingFigure 1~2
  • EP2455455B1 patent drawingFigure 3
  • EP2455455B1 patent drawingFigure 4

AI summary

A new device and method for detecting the presence of living microorganisms in test samples are described. The device comprises a container with at least one section transparent to light, a growth zone located in said container containing a mixture of growth media capable of supporting growth of the microorganisms, and at least one indicator substrate that changes its optical properties due to growth of the microorganisms. A detection zone is located in the container adjacent to the transparent section, and a barrier layer comprising porous solid material separates the two zones, allowing diffusion of molecules and ions of metabolic by-products of the organisms, while preventing microorganisms and particulate matter of the test sample from penetrating into the detection zone.