Colloidal Coomassie Stain Formulation Stability

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Solution Overview

Problem

Current two-part protein stains for electrophoresis gels have a short shelf-life due to rapid precipitate formation and require fresh preparation before each use, with methanol-based formulations posing environmental and safety concerns.

Innovation Solution

A stabilized colloidal stain formulation using Coomassie Brilliant Blue, a polyoxyethylene-containing or poloxamer surfactant, ethanol, and ammonium sulfate, which prevents precipitation and allows for a long-shelf stable 1-part solution, replacing methanol with ethanol for environmental benefits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two-part stain formulation is used, then staining performance is improved, but shelf-life deteriorates due to rapid precipitate formation

Engineering Contradiction:
Improvestaining performanceVSAvoidshelf-life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent combines two separate stain solutions into a single stable formulation by incorporating a non-ionic surfactant. The surfactant prevents precipitation when the stain components are mixed, allowing the formulation to remain stable for extended periods while maintaining the effective staining performance of traditional two-part systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The non-ionic surfactant acts as an intermediary substance that mediates between the stain components and prevents their unwanted interaction (precipitation). The surfactant molecules stabilize the colloidal suspension of the stain, enabling long-term storage without loss of staining effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If methanol is used in the stain formulation, then staining effectiveness is maintained, but environmental safety deteriorates

Engineering Contradiction:
Improvestaining effectivenessVSAvoidenvironmental safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameter of the alcohol component from methanol to ethanol. This substitution maintains the necessary solvent properties and staining effectiveness while eliminating the toxic and environmentally harmful characteristics of methanol, providing a safer alternative with comparable performance.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a colloidal form of Coomassie Brilliant Blue is used, then background staining is reduced, but preparation complexity increases

Engineering Contradiction:
Improvebackground staining controlVSAvoidpreparation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the colloidal Coomassie Brilliant Blue stain with a non-ionic surfactant and ethanol in a single stable formulation. This merging eliminates the need for separate preparation steps to create the colloidal form, as the surfactant stabilizes the colloidal suspension directly in the storage formulation, maintaining low background staining while simplifying the overall process.

Inventive Principle:
Principle #5Merging (Combining)

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

The formulation maintains staining intensity and sensitivity similar to traditional 2-part stains, with extended storage capabilities up to two years, reducing the need for frequent preparation and minimizing environmental impact.

Implementation Method 1

a polyoxyethylene-containing surfactant or a poloxamer surfactant

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 2

The use of Coomassie Brilliant Blue G-250 for staining electrophoresis gels to a defined endpoint is possible because the dye can be formulated as a colloidal form

Methodology Applied
Scientific EffectColloid: Colloid

Implementation Method 3

the dye can be formulated as a colloidal form that does not enter the gel for staining, but rather is adsorbed by the protein bands in the gel, saturating the bands given enough time to diffuse throughout the bands

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

saturating the bands given enough time to diffuse throughout the bands

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 5

ammonium sulfate; and optionally orthophosphoric acid

Methodology Applied
Scientific EffectIonic strength adjustment: Electrolyte

Data Source

PatentEP2972192B1Colloidal coomassie stain
Publication Date: 2018.12.12 BIO RAD LABORATORIES INC
  • EP2972192B1 patent drawingFigure 1
  • EP2972192B1 patent drawingFigure 2
  • EP2972192B1 patent drawing

AI summary

Colloidal formulation for staining proteins and methods of their use are provided.