Porous Conductive Electrodes for Biosensor Miniaturization
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Solution Overview
Problem
Existing biosensors face challenges in miniaturization due to limited electrode area and uneven reagent concentration, leading to reduced sensitivity and accuracy, and are hindered by complex manufacturing processes and equipment costs for environmental control.
Innovation Solution
The biosensor employs porous conductive electrodes and a reagent portion formed within a porous body, such as an insulating fiber mesh cloth, to increase contact area and uniform reagent distribution, enabling efficient miniaturization and improved sensitivity through roll-to-roll manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the fluid path is reduced to minimize sample amount and electrode area, then the biosensor size is reduced, but the contact area between sample and reactive electrode is reduced, leading to reduced output and dispersed sensor sensitivity
Solution Approach 1:
The patent applies porous materials by forming the reactive electrode and counter electrode as porous layers with controlled porosity (30-70%). This porous structure dramatically increases the internal surface area of the electrodes while maintaining a compact external footprint. The sample fluid penetrates into the porous structure, creating extensive contact areas between the sample and electrode surfaces, thereby resolving the contradiction between miniaturization and sensitivity maintenance.
Solution Approach 2:
The patent transitions from two-dimensional planar electrodes to three-dimensional porous structures. By building electrode functionality into the depth dimension through porous networks, the effective electrode surface area is multiplied without increasing the planar footprint of the biosensor. This dimensional transformation allows miniaturization while preserving or even enhancing sensor sensitivity.
2Quantity of substance
If the reagent liquid is dried to form the reagent portion, then the reagent is concentrated, but the circumferential portion dries more rapidly than the center portion, causing uneven reagent concentration and degraded measurement accuracy
Solution Approach 1:
The patent forms the reagent portion within the porous structure of the electrode layers rather than as a surface coating. The porous network provides uniform capillary action throughout the reagent layer, ensuring consistent evaporation rates and homogeneous reagent distribution during the drying process. This eliminates the circumferential-vs-center drying rate differential that plagues conventional surface-coated reagent layers.
Solution Approach 2:
The patent creates a composite structure where reagent-containing particles are embedded within the porous electrode matrix. This composite arrangement ensures uniform reagent distribution throughout the electrode volume and provides a controlled drying environment that prevents edge effects, maintaining homogeneous reagent concentration across the entire reagent portion.
3Reliability
If metal pieces are buried in the substrate to form electrodes, then electrode functionality is achieved, but the substrate thickness must be increased, making roll-to-roll manufacturing impossible
Solution Approach 1:
The patent forms electrodes as porous layers deposited onto or within thin substrate structures, eliminating the need to bury metal pieces deep within thick substrates. The porous electrode layers provide sufficient electrical functionality with minimal substrate thickness, enabling flexible substrates to be used and making roll-to-roll manufacturing feasible.
Solution Approach 2:
The patent replaces the mechanical embedding of metal pieces (which requires thick substrates and complex assembly) with thin-film deposition techniques for forming porous conductive layers. This substitution of manufacturing methodology enables the use of thin, flexible substrates that can be processed in roll-to-roll manufacturing systems.
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 sensor sensitivity and measurement accuracy while simplifying manufacturing and reducing costs by increasing the electrode contact area and uniformizing reagent concentration, facilitating efficient and cost-effective miniaturization of the biosensor.
Implementation Method 1
The porous conductive portion is obtained by coating a conductive film on at least part of a surface and an inner surface of a porous body
Implementation Method 2
when the reagent portion 96 is dissolved by the sample, the solubility of the reagent portion 96 is degraded
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to an analysis tool (1) including a reagent portion (7) and electrodes (3, 5). The electrodes (3, 5) include a porous conductive portion where the reagent portion (7) is formed. The porous conductive section is formed by, for instance, coating at least a part of a surface and an inner surface of a porous body with a conductive film. The porous body is, for instance, an insulating fiber mesh cloth. Preferably, the electrodes (3, 5) are formed in a sheet shape.