Membrane Carrier Microstructure for Sensitive POCT Detection

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Solution Overview

Problem

Current Point of Care Testing (POCT) reagents using nitrocellulose membranes are limited by the small size of marker particles, which restricts sensitivity due to clogging issues and non-uniform pore sizes, preventing the effective use of larger latex particles that could enhance detection sensitivity.

Innovation Solution

A membrane carrier with a microstructure and flow path design that allows particles of 500 nm to 100 µm in diameter, bound with antibodies or antigens, to be used for highly sensitive detection, enabling the use of multiple particle sizes for improved sensitivity and reducing clogging risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nitrocellulose membrane with micropores is used, then liquid sample can move through capillary force, but the pore size is too fine (several μm) to allow larger marker particles, limiting detection sensitivity

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmarker particle diameter
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The invention changes the pore size parameter of the membrane from conventional several μm to 10 μm or more, enabling the use of larger marker particles (500 nm to 100 μm) while maintaining capillary flow functionality. This parameter change directly resolves the contradiction by allowing larger particles to pass through without clogging.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces a dual-layer membrane structure where the first layer has larger pores (10 μm or more) for particle transport and the second layer has smaller pores for detection. This dynamic functional division allows different particle sizes to be used while maintaining both flow and detection capabilities.

Inventive Principle:
Principle #15Dynamics

2Reliability

If nitrocellulose membrane with non-uniform pore sizes is used, then manufacturing is simplified, but clogging occurs with larger particles and detection sensitivity is reduced

Engineering Contradiction:
Improvedetection sensitivityVSAvoidclogging
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the pore size parameter to 10 μm or more, which is large enough to prevent clogging with marker particles of 500 nm to 100 μm diameter, while maintaining uniform pore distribution to ensure consistent flow and detection performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a porous membrane with specifically controlled pore size (10 μm or more) that allows marker particles to pass through freely without clogging, while still providing sufficient surface area for detection reactions. The porous structure enables both high particle throughput and effective detection.

Inventive Principle:
Principle #31Porous materials

3Reliability

If smaller marker particles are used to avoid clogging, then flow through membrane is maintained, but detection sensitivity is limited

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurable concentration range
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention changes the marker particle diameter parameter to 500 nm or more, leveraging the enlarged membrane pores to allow larger particles that provide enhanced detection sensitivity and extended measurable concentration range without causing clogging.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a porous membrane with 10 μm or more pore size that accommodates larger marker particles, enabling the use of particle sizes that optimize both sensitivity and measurable concentration range while preventing clogging through the enlarged pore structure.

Inventive Principle:
Principle #31Porous materials

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 membrane carrier enables highly sensitive detection of target substances by allowing larger particles to be used, increasing the measurable concentration range and improving detection sensitivity while minimizing clogging issues.

Implementation Method 1

a microstructure formed at a bottom of the flow path

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

an antibody or an antigen bound to the particle, wherein the antibody and antigen can react specifically with a target substance

Methodology Applied
Scientific EffectAntigen-antibody reaction:

Data Source

PatentEP3605099B1Membrane carrier, kit for testing liquid sample using same, and manufacturing method thereof
Publication Date: 2022.03.09 DENKA CO LTD
  • EP3605099B1 patent drawingFigure 1
  • EP3605099B1 patent drawingFigure 2
  • EP3605099B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention provides a membrane carrier 3 comprising a flow path 2, wherein a microstructure is formed at a bottom of the flow path 2, and a particle to which an antibody or an antigen binds is arranged in at least a part on the flow path, the particle having a diameter of 500 nm or more and 100 µm or less.