Transparent Conductive Film Laminate for High-Sensitivity ECL Biochips

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Solution Overview

Problem

Existing electrochemiluminescence (ECL) immunoassay devices are challenging to miniaturize and integrate with disposable immunochromatography due to the need for electrodes and membrane thickness, leading to reduced luminescence efficiency and sensitivity, especially in point-of-care testing (POCT) applications.

Innovation Solution

A laminated body comprising a transparent conductive film, such as graphene, with a permeable porous membrane that allows electrolyte solution transport, enabling efficient electrochemiluminescence immunoassays by immobilizing proteins on the porous membrane, which does not contain rare elements and can be used as a disposable electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick membrane (about 100 μm) is used in immunochromatography, then the membrane provides sufficient mechanical strength and binding capacity, but the reactive species generated by electrode reaction become deactivated before reaching the electrochemiluminescent labeling substances, significantly reducing luminescence efficiency

Engineering Contradiction:
Improvemechanical strengthVSAvoidluminescence efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent divides the membrane into two distinct layers: a thin porous membrane layer (10-50 μm) for electrochemiluminescence detection close to the electrode, and a separate nitrocellulose membrane layer for immunochromatographic separation. This segmentation allows each layer to perform its optimal function while overcoming the thickness limitation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical layering structure where the thin porous membrane is positioned immediately adjacent to the electrode surface, creating a short diffusion path for reactive species. The immunochromatography function is achieved through a separate layer above it, effectively solving the thickness problem by utilizing the vertical dimension.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional opaque electrodes are used in ECL immunoassay, then the electrode provides sufficient electrical conductivity and mechanical strength, but the device cannot be miniaturized and integrated with disposable immunochromatography for POCT applications

Engineering Contradiction:
Improveelectrical conductivityVSAvoidminiaturization capability
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a thin transparent conductive film (such as ITO, 50-200 nm thick) as the electrode, replacing conventional thick opaque electrodes. This thin film structure provides sufficient electrical conductivity while enabling light transmission for luminescence detection and allowing integration with disposable immunochromatography strips for miniaturized POCT devices.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure combining a transparent conductive oxide film with a porous polymer membrane layer. This composite material integrates the electrical conductivity of the transparent film with the porous structure needed for reagent transport and binding, enabling both miniaturization and functional performance.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If a thin porous membrane is used to reduce the distance for reactive species diffusion, then the luminescence efficiency is improved, but the mechanical strength and binding capacity are reduced

Engineering Contradiction:
Improveluminescence efficiencyVSAvoidbinding capacity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent segments the functional requirements into two separate layers: the thin porous membrane provides luminescence detection capability close to the electrode, while the separate nitrocellulose membrane layer provides sufficient binding capacity for immunochromatography. This segmentation resolves the contradiction between thickness and function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges two separate membrane functions (luminescence detection and immunochromatography) into a single integrated device structure, where each function is performed by a dedicated layer that works in conjunction with the other, achieving both thinness for efficiency and sufficient binding capacity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4691756A1Laminate including transparent electroconductive film and porous film, biochip including laminate, and method for manufacturing these
Publication Date: 2026.02.11 WATANABE TAKESHI
  • EP4691756A1 patent drawingFigure 1~3
  • EP4691756A1 patent drawingFigure 4A~4E
  • EP4691756A1 patent drawingFigure 4F~4G

AI summary

[Problem] To provide a transparent electroconductive film that can be supplied for use in quick and simple inspection equipment, and a biochip in which the transparent electroconductive film is used. In particular, to provide a transparent electroconductive film that can be used for immunoassay utilizing electrochemical light emission, and a biochip in which the transparent electroconductive film is used. [Solution] The present invention provides a laminate comprising a transparent electroconductive film and a porous film that is laminated on the transparent electroconductive film, wherein the porous film is permeable with respect to an electrolyte solution.