Non-Porous Substrate Projections for Lateral Capillary Flow

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Solution Overview

Problem

Conventional nitrocellulose-based assay devices face challenges with non-specific binding of proteins and variable quality, leading to inefficiencies in sample handling and reagent usage, particularly in miniaturized diagnostic tests where sample volume and reagent amounts need to be minimized without compromising accuracy and reliability.

Innovation Solution

The use of a non-porous substrate with projections perpendicular to the surface, optimizing height, diameter, and distance between projections to achieve lateral capillary flow, along with modifying the surface for desired chemical, biological, or physical functionality, allows for efficient fluid transport and absorption in assay devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nitrocellulose material is used as the transport or reaction zone, then fluid transport capability is provided, but non-specific binding of proteins and other bio-molecules occurs and quality is variable

Engineering Contradiction:

Improvefluid transport reliabilityVSAvoidnon-specific binding

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful non-specific binding property is extracted from the system by replacing nitrocellulose with alternative materials such as polyester, polypropylene, or polystyrene that do not exhibit this unwanted binding behavior, while maintaining the essential fluid transport function through capillary channels

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The chemical composition parameter of the transport zone material is changed from nitrocellulose to synthetic polymers with different surface properties, fundamentally altering the binding characteristics while preserving the physical capillary transport mechanism

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If sample volume is minimized in line with miniaturization trends, then device size and reagent amounts are reduced, but accuracy and reliability may be compromised

Engineering Contradiction:

Improvesample volumeVSAvoidtest accuracy

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Different zones of the device are optimized with specific material properties - the transport zone uses non-binding synthetic polymers while the detection zone incorporates appropriate substrates, allowing minimal sample volumes to be handled efficiently without compromising the reliability of the detection function

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The reliance on large sample volumes for reliable detection is replaced by a optimized capillary transport system that ensures complete and controlled delivery of minimal sample volumes to the detection zone, substituting volume-dependent reliability with mechanism-dependent reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If excess sample is used to reduce non-specific binding influence, then reliability is improved, but sample volume and reagent consumption increase

Engineering Contradiction:

Improvebinding accuracyVSAvoidsample volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The potential harm of non-specific binding on nitrocellulose is converted into a benefit by using the material's high binding capacity in the detection zone while employing excess-free sample volumes, as the non-specific binding issues are eliminated by material substitution rather than compensated by excess sample

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enables reliable and accurate fluid transport and absorption, reducing the need for excess sample and reagents, improving the sensitivity and reliability of diagnostic tests, and facilitating the production of compact, cost-effective disposable devices.

Implementation Method 1

said projections having a height (H), diameter (D) and a distance or distances between the projections (t1, t2) such, that lateral capillary flow of said fluid in said zone is achieved

Methodology Applied

Scientific EffectCapillary flow: Capillary Action

Implementation Method 2

an absorbing zone specifically adapted to establish, maintain and/or meter fluid transport through or along said at least one fluid passage

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS8821812B2Method and means for creating fluid transport

Publication Date: 2014.09.02 CRIMSON INTERNATIONAL ASSETS LLC

AI summary

An absorbing zone for establishing and/or maintaining fluid transport through or along at least one fluid passage is manufactured on the basis of a non-porous substrate having a surface, the non-porous substrate having projections substantially perpendicular to the surface, and the projections having a height, diameter and a distance or distances between the projections such, that lateral capillary flow of the fluid in the zone is achieved.