IDF Permeabilization for Mycobacterium Detection

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Solution Overview

Problem

Current methods for cell permeabilization after fixation are either ineffective, too rigorous, or require expensive equipment, making it difficult to detect internal cellular components, especially for Mycobacterium species due to their thick cell walls, which hinder the delivery of probes for detection and differentiation.

Innovation Solution

The use of an IDF solution comprising chaotropic salts, ionic and non-ionic detergents, and other reagents to create channels in cell walls and membranes, allowing probes to penetrate and detect nucleic acids or proteins within Mycobacterium cells, even after fixation, using methods like in situ hybridization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If fixation is performed to preserve cellular structure, then cellular molecules are set in place and degradation is prevented, but the ability to detect internal cellular components is hampered

Engineering Contradiction:
Improvecellular structure preservationVSAvoiddetection of internal cellular components
Core Design Contradiction:
Stability of the object's compositionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by performing permeabilization treatment on fixed cells before probe hybridization. The IDF solution is applied to create channels in the cell wall and membrane structures after fixation, allowing probes to penetrate and detect internal components while the fixed structure remains preserved. This sequence resolves the contradiction by preparing the cell for detection without compromising the preserved state.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary substance - the IDF solution comprising chaotropic salts, detergents, and other reagents - to mediate between the fixed cellular structure and the detection probes. This intermediary creates permeable channels that allow probe penetration while maintaining the fixed state of cellular molecules, thus resolving the contradiction between preservation and detectability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If standard lysis procedures with detergents are used to access internal components, then nucleic acids can be released, but the thick mycolate-rich cell wall of Mycobacterium prevents effective penetration

Engineering Contradiction:
Improveaccess to nucleic acidsVSAvoidcell wall barrier integrity
Core Design Contradiction:
Difficulty of detecting and measuringVSStrength

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition and concentration parameters of the permeabilization solution. The IDF solution contains specific concentrations of chaotropic salts (0.5-4.5M), detergents (0.1-2.0%), and other reagents that are optimized to interact with the mycolate-rich cell wall. These parameter adjustments enable effective penetration through the thick cell wall while maintaining cell wall integrity during fixation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite permeabilization solution containing multiple components working together - chaotropic salts, ionic and non-ionic detergents, and other reagents in specific proportions. This composite formulation synergistically interacts with the mycolate-rich cell wall to create permeable channels, overcoming the barrier that would be insurmountable by any single agent.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If mechanical methods such as sonication or electroporation are used for permeabilization, then cell membranes can be disrupted, but expensive equipment is required and the methods usually only work on unfixed samples

Engineering Contradiction:
Improvepermeabilization effectivenessVSAvoidequipment requirements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical permeabilization methods (sonication, electroporation) with a chemical permeabilization system. The IDF solution chemically disrupts the cell wall and membrane structures through chaotropic salts and detergents, eliminating the need for expensive mechanical equipment while maintaining effectiveness on fixed samples. This substitution resolves the contradiction by achieving permeabilization through chemistry rather than mechanics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Difficulty of detecting and measuring

If rigorous permeabilization methods are used to create channels in cell membranes, then probe penetration is improved, but the structures to be studied are destroyed

Engineering Contradiction:
Improveprobe penetration abilityVSAvoidcellular structure integrity
Core Design Contradiction:
Difficulty of detecting and measuringVSStrength

Solution Approach 1:

The patent applies local quality by creating localized channels or pores in specific regions of the cell wall and membrane while maintaining the integrity of the overall cellular structure. The IDF solution selectively permeabilizes the cell envelope to allow probe penetration without destroying the fixed cellular molecules and structures that need to be studied. This localized approach resolves the contradiction between penetration and structural integrity.

Inventive Principle:
Principle #3Local quality

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 enhances the sensitivity and accuracy of detecting and differentiating Mycobacterium species by improving probe penetration and retention of cellular components, facilitating more effective diagnostic methods for clinical samples and cultures.

Implementation Method 1

The use of an IDF solution comprising chaotropic salts, ionic and non-ionic detergents, and other reagents to create channels in cell walls and membranes

Methodology Applied
Scientific EffectChaotropic salt effect:

Implementation Method 2

The use of an IDF solution comprising chaotropic salts, ionic and non-ionic detergents, and other reagents to create channels in cell walls and membranes

Methodology Applied
Scientific EffectDetergent permeabilization: Surfactant

Implementation Method 3

allowing probes to penetrate and detect nucleic acids or proteins within Mycobacterium cells, even after fixation, using methods like in situ hybridization

Methodology Applied
Scientific EffectHybridization:

Data Source

PatentUS8758990B2Methods for detecting and differentiating Mycobacterium genus and Mycobacterium avium complex in a sample or culture
Publication Date: 2014.06.24 ID FISH TECHNOLOGY INC

AI summary

The present invention relates to compositions and methods for detecting Mycobacterium genus (Mycobacterium sp.) bacteria (e.g., M. tuberculosis) and M. avium complex (MAC; M. avium, M. scrofulaceum and M. intracellulaire) in a clinical sample or culture. The present invention also relates to differentiating cultures or samples comprising (Mycobacterium sp.) bacteria (e.g., M. tuberculosis) from cultures or samples comprising M. avium complex (MAC; M. avium, M. scrofulaceum and M. intracellulaire).