Capillary Biosensor Layout for Oxygen-Free Small-Volume Detection

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Solution Overview

Problem

Existing electrochemical biosensors face inaccuracies due to the influence of oxygen, particularly in small sample volumes, leading to significant measurement errors and increased complexity and cost in sensor design.

Innovation Solution

A biosensor design with a capillary detection chamber of ≤ 10 µl volume, incorporating a working electrode, counter electrode, and an oxygen-binding inerting agent positioned between the electrode and inlet, adapted to completely remove oxygen before it reaches the detection area, ensuring effective and reliable analyte detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If correction methods are used to account for oxygen influence, then measurement accuracy is improved, but device complexity and cost increase due to additional electrodes

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidsensor design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes oxygen from the detection environment by introducing an inert gas (nitrogen or argon) into the detection chamber, isolating the analyte detection process from oxygen interference. This eliminates the need for additional correction electrodes while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates an inert atmosphere in the detection chamber by filling it with nitrogen or argon gas, which prevents oxygen from interfering with the electrochemical detection process. This inert environment protects the measurement accuracy without requiring complex additional electrodes or correction mechanisms.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Measurement precision

If GO-based test systems are used for glucose detection, then specificity for glucose is improved, but measurement accuracy deteriorates due to sensitivity to oxygen concentration changes

Engineering Contradiction:
Improveglucose detection specificityVSAvoidmeasurement stability under varying oxygen conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent creates an oxygen-free inert atmosphere in the detection chamber using nitrogen or argon gas, which protects the glucose oxidase enzyme from oxygen concentration variations. This allows GO-based systems to maintain both their glucose specificity and measurement reliability under varying oxygen conditions.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent applies preliminary anti-action by pre-filling the detection chamber with inert gas before introducing the sample, thereby preventing oxygen from interfering with the glucose oxidase reaction. This proactive measure eliminates oxygen-related measurement instability before it can affect the detection process.

Inventive Principle:
Principle #9Preliminary anti-action

3Productivity

If small sample volumes are used for detection, then productivity is improved, but measurement accuracy deteriorates due to greater oxygen influence

Engineering Contradiction:
Improvedetection speedVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates an inert atmosphere in the detection chamber that prevents oxygen from diffusing into small sample volumes. This protects the measurement accuracy of small samples while maintaining the productivity benefits of rapid detection, as the inert gas barrier eliminates oxygen interference regardless of sample volume.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent introduces inert gas as an intermediary substance between the external oxygen environment and the small sample volume in the detection chamber. This intermediary layer prevents oxygen from reaching and interfering with the analyte, maintaining measurement accuracy even in small volumes used for high-productivity applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The biosensor achieves accurate, oxygen-independent analyte detection in small volumes, simplifying production and reducing costs by optimizing the interaction of inerting agent parameters with chamber dimensions.

Implementation Method 1

an oxygen-binding or oxygen-reactive inerting agent is provided in the capillary detection chamber

Methodology Applied
Scientific EffectOxygen binding: Absorption (physical)

Implementation Method 2

an oxygen-binding or oxygen-reactive inerting agent is provided in the capillary detection chamber

Methodology Applied
Scientific EffectOxygen reaction: Chemical Bonding

Implementation Method 3

a working electrode having a measuring area positioned in the capillary detection chamber and provided with an immobile detection agent for interacting with the analyte

Methodology Applied
Scientific EffectEnzyme-substrate interaction: Enzyme

Data Source

PatentEP3807626B1Biosensor, method for detecting with said biosensor, method for producing and use of said biosensor
Publication Date: 2026.04.22 RUHR UNIV BOCHUM
  • EP3807626B1 patent drawingFigure 1(I)~2c
  • EP3807626B1 patent drawingFigure 3a~3d
  • EP3807626B1 patent drawingFigure 4a~6

AI summary

An electrochemical biosensor (10) for detecting at least one analyte dissolved in an analyte solvent comprises a capillary detection chamber (12) and a plurality of electrodes, wherein the plurality of electrodes (14, 16, 18) comprise at least one working electrode (14) that has a measuring region (20) positioned in the capillary detection chamber (12), said measuring region being provided with an immobile detection means (22) for interaction with the analyte, and wherein the plurality of electrodes further comprises a counter electrode (16) that extends into the capillary detection chamber (12) and wherein the plurality of electrodes (14, 16, 18) are electrically contactable outside of the capillary detection chamber (12), wherein the capillary detection chamber (12) has a volume in a region of ≤ 10 μl, wherein, further, an oxygen-binding or oxygen-reactive inerting agent (26), which is positioned at least partly between the working electrode (14) and an inlet opening (28) of the capillary detection chamber (12), is provided in the capillary detection chamber (12) and wherein the length of the capillary detection chamber (12) between the working electrode (14) and the inlet opening (28) and the inerting agent (26) are chosen and matched to one another in such a way that oxygen diffusing from the inlet opening (28) in the direction toward the working electrode (14) in the analyte solvent disposed in the detection chamber (12) is completely removable from the analyte solvent by the inerting agent (26) before reaching the working electrode (14).