Immunochromatography Test Kit Pad Absorbency Design

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Solution Overview

Problem

Test kits using immunochromatography face challenges in achieving rapid and highly sensitive detection due to retention of labeling substances in the labeling substance holding pad, which inhibits their development to the test line.

Innovation Solution

The test kit design includes a dropping pad with lower absorbency and a labeling substance holding pad with higher absorbency, where the labeling substance is uniformly held in a containing portion, and a non-containing portion with uniform absorbency at the upstream end, preventing backflow and facilitating rapid development to the detection zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the labeling substance holding pad has high absorbency to retain labeling substance, then the labeling substance can be held uniformly, but the labeling substance development to the test line is inhibited

Engineering Contradiction:
Improvelabeling substance retentionVSAvoidlabeling substance development speed
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The labeling substance holding pad is divided into a first region (upstream) with lower absorbency and a second region (downstream) with higher absorbency. This segmentation allows the first region to facilitate rapid liquid sample flow and labeling substance development, while the second region effectively retains the labeling substance for detection, thus resolving the contradiction between retention and development speed.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the labeling substance is held uniformly in the labeling substance holding pad, then the detection is sensitive, but the labeling substance is retained and cannot flow to the detection zone efficiently

Engineering Contradiction:
Improvedetection sensitivityVSAvoiddetection efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Different regions of the labeling substance holding pad are assigned different absorbency properties: the first region has lower absorbency to enable efficient flow and development, while the second region has higher absorbency to ensure sensitive detection. This local quality differentiation allows the system to achieve both high detection sensitivity and efficient processing.

Inventive Principle:
Principle #3Local quality

3Speed

If the liquid sample flows rapidly through the labeling substance holding pad, then rapid detection is achieved, but the labeling substance may flow back to upstream regions

Engineering Contradiction:
Improveliquid sample flow speedVSAvoidflow direction stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The labeling substance holding pad is segmented into regions with different absorbency characteristics. The upstream first region has lower absorbency to allow rapid flow, while the downstream second region has higher absorbency to act as a barrier preventing backflow, thus maintaining flow direction stability while enabling rapid detection.

Inventive Principle:
Principle #1Segmentation

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 configuration enables rapid and sensitive detection by preventing labeling substance retention and ensuring efficient flow to the detection zone, allowing for accurate identification of the test line.

Implementation Method 1

allowing a liquid sample to develop downstream by capillary phenomenon

Methodology Applied
Scientific EffectCapillary phenomenon: Capillary Action

Implementation Method 2

an absorbent pad c, which takes up the liquid sample downstream of the kit body b

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2975407B1Examination kit
Publication Date: 2019.08.07 DENKA SEIKEN CO LTD
  • EP2975407B1 patent drawingFigure 1
  • EP2975407B1 patent drawingFigure 2
  • EP2975407B1 patent drawingFigure 3

AI summary

The present invention provides a test kit capable of rapid and highly sensitive detection. The test kit has a dropping region, which contains a portion onto which a liquid sample drops, a labeling substance holding region, at least a portion of which is connected downstream of the dropping region in the developing direction, and in which a labeling substance with a label immobilized on a substance that specifically binds with the substance to be detected is held, a developing region, which has a detection zone where the labeling substance is captured through the substance to be detected, at least a portion of which is connected downstream of the labeling substance holding region in the developing direction, and which allows the labeling substance having been made to flow out from the labeling substance holding region by the liquid sample, to develop into the detection zone, and retention inhibition means for inhibiting retention of the labeling substance in the labeling substance holding region when the liquid sample develops downstream.