Biosensor Reagent Layer Geometry for Measurement Accuracy
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Solution Overview
Problem
Existing biosensors face challenges in achieving highly accurate measurements due to the positional relationship between the reagent layer and the working and counter electrodes, which affects the reaction system and measurement accuracy.
Innovation Solution
A biosensor design featuring a substrate with a conductive part including a working electrode and a counter electrode, a reagent layer covering the entirety of the working electrode within a flow channel and extending beyond its edges, and covering at least 70% of the counter electrode's surface area within the flow channel, with an average reagent layer thickness of 4 μm to 12 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reagent layer is applied using conventional methods (dipping, dispensing, screen printing), then the application process is simple, but the positional relationship between the reagent layer and electrodes cannot be precisely controlled, resulting in poor measurement accuracy
Solution Approach 1:
The patent specifies precise dimensional parameters for the reagent layer: width of 0.6 mm to 1.4 mm, length of 2.0 mm to 4.0 mm, and thickness of 4 μm to 12 μm. These parameter controls ensure the reagent layer covers the working electrode completely while extending appropriately, and covers at least 70% of the counter electrode, thereby achieving accurate measurement through controlled geometry rather than complex positioning mechanisms
Solution Approach 2:
The reagent layer is designed to extend beyond the edges of the working electrode by at least 50 μm upstream and downstream. This preliminary extension ensures that even with manufacturing variations, the reagent layer maintains proper coverage of the electrode surfaces, pre-establishing the correct positional relationship before the actual measurement process begins
2Measurement precision
If the reagent layer thickness is not controlled, then the manufacturing process is simpler, but the measurement accuracy deteriorates
Solution Approach 1:
The patent establishes a specific thickness range of 4 μm to 12 μm for the reagent layer. This parameter control ensures sufficient reagent content for accurate measurement while preventing excessive thickness that could cause diffusion issues or manufacturing difficulties. The defined range balances measurement precision with manufacturing feasibility
3Reliability
If the reagent layer covers only the electrode surface without extension, then the material usage is reduced, but the reaction efficiency and measurement accuracy decrease
Solution Approach 1:
The reagent layer extends at least 50 μm beyond the upstream and downstream edges of the working electrode. This preliminary extension creates a buffer zone that ensures complete coverage during sample flow, improving reaction efficiency by ensuring all electrode surfaces are adequately covered without requiring excessive material
Solution Approach 2:
The reagent layer covers not only the entire working electrode but also extends to cover at least 70% of the counter electrode surface. This partial extension beyond the minimum required area ensures reliable reaction efficiency while controlling material usage through defined coverage ratios rather than complete coverage of all electrodes
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 design enables highly accurate measurement of analytes by ensuring comprehensive coverage of the electrodes with the reagent layer, enhancing the reaction efficiency and measurement precision.
Implementation Method 1
the measurement target, such as blood glucose, contained in a sample, such as blood, reacts with a reagent in the reagent layer, and the reaction is detected
Data Source
AI summary
According to an aspect, provided is a biosensor capable of highly accurate measurement. The present disclosure relates, in an aspect, to a biosensor including: a substrate with a conductive part provided on one main surface, the conductive part including an electrode pair having a working electrode and a counter electrode; a reagent layer placed on the working electrode and the counter electrode; and a flow channel for allowing a sample to flow from a sample supply port to the reagent layer.