Multi-Layer Microbial Detection Article With Barrier Layer

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Solution Overview

Problem

Current methods for detecting microorganisms on surfaces in food processing and healthcare facilities are inefficient, leading to potential health risks due to microbial contamination and transfer, as they often require lengthy exposure to detection reagents that can inhibit microbial growth and cause overlapping indicator zones, making it difficult to distinguish between multiple microorganism colonies.

Innovation Solution

A multi-layer detection article comprising a base member with a cold water-soluble gelling agent, a microporous membrane, and a removable barrier layer, which allows for controlled exposure to a detection reagent, enabling the growth of microorganisms before exposure, thereby reducing the time needed for detection and minimizing the diffusion of indicator zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If microorganisms are exposed to detection reagents for a long period, then detection sensitivity is improved, but microbial growth is inhibited and indicator zones overlap making colony distinction difficult

Engineering Contradiction:
Improvedetection sensitivityVSAvoidcolony distinction capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection article is divided into distinct functional layers: a base member with nutrient coating for microbial growth, a microporous membrane for physical separation, and a cover sheet with detection reagent. This segmentation allows simultaneous optimization of growth conditions and detection capability without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A microporous membrane serves as an intermediary layer between the microbial growth environment and the detection reagent. This membrane allows nutrient and water vapor transmission while physically preventing direct contact between reagents and microorganisms during the growth phase, enabling sequential optimization of both growth and detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If detection reagent exposure time is extended, then detection accuracy improves, but the time required for complete detection process increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidtotal detection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The base member is pre-coated with nutrient material before use, creating a ready-to-support growth environment. This preliminary preparation eliminates the need for adding nutrients during the detection process, allowing immediate inoculation and reducing overall detection time while maintaining accurate detection capabilities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The detection process is divided into distinct periodic phases: an initial growth phase where microorganisms multiply on the nutrient-coated base member, followed by a detection phase where the cover sheet with reagents is applied. This periodic separation optimizes each phase independently, reducing total time while maintaining accuracy.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If a single-layer detection article is used, then device complexity is reduced, but control over microbial growth and reagent exposure is insufficient

Engineering Contradiction:
Improvearticle structureVSAvoidgrowth and detection control
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The detection article is divided into distinct functional layers: a base member with nutrient coating for microbial growth, a microporous membrane for physical separation, and a cover sheet with detection reagent. This segmentation allows simultaneous optimization of growth conditions and detection capability without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multilayer structure provides dynamic control over the detection process. The microporous membrane can be removed or adjusted to transition between growth mode (membrane in place, allowing nutrient transmission) and detection mode (membrane removed, allowing reagent contact), enabling adaptive optimization throughout the detection sequence.

Inventive Principle:
Principle #15Dynamics

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 rapid and accurate detection of microorganisms by reducing exposure time to detection reagents, improving resolution between multiple colonies, and preventing the spread of microorganisms during the detection process, thus enhancing safety and efficiency in identifying pathogens like Staphylococcus aureus and Listeria monocytogenes.

Implementation Method 1

The microporous membrane can be disposed between the base member and the barrier layer

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

The upper major surface of the base member can comprise a first dry coating that includes a cold water-soluble gelling agent

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

The barrier layer can be configured to form a fluid barrier between the microporous membrane and the cover sheet

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP2519821B1Microbial detection article
Publication Date: 2016.11.30 3M INNOVATIVE PROPERTIES CO
  • EP2519821B1 patent drawingFigure 1a~1b
  • EP2519821B1 patent drawingFigure 1c~2
  • EP2519821B1 patent drawingFigure 3a~3b

AI summary

The disclosure provides an article for the detection of a microorganism in a liquid sample. The article comprises a microporous membrane and a barrier layer to selectively regulate the contact between the sample and a detection reagent. A method of use is also provided.