Electrophoretic Dot Blot Fixation for Protein Detection
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Solution Overview
Problem
Current dot blot filtration techniques are limited by sample preparation methods, particularly the use of chaotropic agents like SDS, which hinder target capture on filtration membranes, and are inefficient due to device geometry, filtration variability, and non-specific antibody binding issues.
Innovation Solution
The method involves applying a perpendicular electric field in conjunction with a pressure differential across a filtration membrane to improve target fixation, even in the presence of detergents, and includes a device with optimized electrode and membrane configurations to enhance ergonomics and specificity of protein detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chaotropic agents such as SDS are added to extract targets of interest, then extraction efficiency is improved, but target capture by filtration membranes deteriorates
Solution Approach 1:
The patent replaces the mechanical filtration process with an electrophoretic process. Instead of relying on passive filtration through membranes that are incompatible with SDS, the invention uses an electric field to drive charged biomolecules through a porous support. This substitution allows the use of chaotropic agents for extraction while maintaining reliable target capture, as electrophoresis is not hindered by the presence of SDS.
Solution Approach 2:
The patent changes the fundamental parameter of the separation process from pressure-driven filtration to electric field-driven electrophoresis. By applying a voltage gradient across the porous support, charged molecules are migrated and focused into sharp bands, achieving both efficient extraction (with SDS compatible conditions) and reliable capture/detection of targets.
2Measurement precision
If well volume is increased to improve detection sensitivity, then detection sensitivity is improved, but membrane surface area increases requiring significant volumes of expensive reagents
Solution Approach 1:
The patent transitions from a planar filtration approach to a three-dimensional electrophoretic process within the porous support. The electric field creates concentrated bands of biomolecules vertically within the support matrix, achieving high detection sensitivity without requiring large membrane surface areas. This dimensional approach allows compact device geometry while maintaining sensitivity.
Solution Approach 2:
By changing from pressure filtration to electric field-driven electrophoresis, the patent achieves concentration of biomolecules into sharp bands within the porous support. This parameter change allows for highly sensitive detection in a compact format, reducing the required membrane surface area and consequently the volume of expensive detection reagents needed.
3Ease of operation
If filtration is applied to samples with different viscosities, then sample processing is simplified, but filtration rate varies from one well to another
Solution Approach 1:
The patent replaces the pressure-driven filtration mechanism with an electric field-driven electrophoretic mechanism. Since electrophoresis is driven by electric field strength and molecular charge rather than pressure gradients, samples with different viscosities are processed at rates determined by their electrophoretic mobility. This substitution eliminates the viscosity-dependent variability inherent in pressure filtration while maintaining ease of operation.
4Speed
If pressure difference is applied to drive filtration, then filtration speed is improved, but pressure drop decreases as wells are emptied making conditions uncontrolled
Solution Approach 1:
The patent replaces pressure-driven filtration with electric field-driven electrophoresis. The electrophoretic migration speed is controlled by the applied voltage and the electrophoretic mobility of the molecules, not by pressure gradients. This substitution maintains fast processing speeds while providing reliable control of migration conditions throughout the entire process, as the electric field can be maintained constant regardless of sample depletion in individual wells.
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 fixation of targets on the membrane, reduces labeling time and non-specific binding, and increases the sensitivity and specificity of protein detection, particularly for phosphorylated proteins, while minimizing the use of reagents and analysis volume.
Implementation Method 1
a method for fixing all or part of a plurality of biological samples onto a spot matrix fixation membrane so as to submit each sample to the simultaneous or sequential action of an electric field and a pressure
Implementation Method 2
a pressure difference ΔP, applied across the membrane, filters the biological sample through the membrane
Data Source
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AI summary
The invention relates to a method and a device for fixing biological samples on a membrane, in a dot matrix, such that each sample undergoes the simultaneous or sequential action of an electric field and a pressure such that the electric field has a direction perpendicular to the fixing membrane, and a differential of potential between the two faces of the fixing membrane, and such that the pressure presents a differential of pressure ΔΡ between the two faces of the membrane.