Electrochemical Biosensor Charge Accumulation for Low-Concentration Detection

Solution Overview

Problem

Existing electrochemical biosensors are inadequate for detecting analytes at low concentrations, such as those below 5 mM, as they do not effectively accumulate and measure the charge derived from enzymatic reactions.

Innovation Solution

A method utilizing a working electrode with an analyte-specific enzyme and a redox mediator, combined with carbon nanotubes, allows for charge accumulation by disconnecting the electrode from the circuit for a set period, followed by reconnecting to measure the accumulated charge, enhancing sensitivity through accumulation mode sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional amperometry is used for analyte detection, then the measurement is simple and continuous, but the sensitivity is insufficient for low concentration analytes (below 5 mM)

Engineering Contradiction:

Improvedetection sensitivityVSAvoidmeasurement process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing charge accumulation during a predetermined time period before the actual measurement. The working electrode is disconnected from the circuit during this accumulation phase, allowing charge to build up from enzymatic reactions. This pre-accumulation of charge enhances the subsequent measurement signal, enabling detection of low concentration analytes that would be undetectable using traditional continuous amperometry alone.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If charge accumulation is implemented by disconnecting the electrode from the circuit, then sensitivity increases for low concentration detection, but the measurement process becomes more complex and time-consuming

Engineering Contradiction:

Improvedetection limitVSAvoidmeasurement cycle time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements periodic action by alternating between two distinct phases: an accumulation phase where the electrode is disconnected from the circuit to build up charge, and a measurement phase where the electrode is connected to measure the accumulated charge. This periodic switching enables the system to achieve high sensitivity for low concentration analytes while maintaining a structured, repeatable measurement cycle that can be optimized for different application requirements.

Inventive Principle:

Principle #19Periodic action

3Speed

If the working electrode is continuously connected to the circuit for amperometric measurement, then real-time monitoring is achieved, but charge accumulation and sensitivity enhancement are prevented

Engineering Contradiction:

Improveresponse timeVSAvoidsignal strength

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing charge accumulation during a predetermined time period before the actual measurement. The working electrode is disconnected from the circuit during this accumulation phase, allowing charge to build up from enzymatic reactions. This pre-accumulation of charge enhances the subsequent measurement signal, enabling detection of low concentration analytes that would be undetectable using traditional continuous amperometry alone.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic action by alternating between two distinct phases: an accumulation phase where the electrode is disconnected from the circuit to build up charge, and a measurement phase where the electrode is connected to measure the accumulated charge. This periodic switching enables the system to achieve high sensitivity for low concentration analytes while maintaining a structured, repeatable measurement cycle that can be optimized for different application requirements.

Inventive Principle:

Principle #19Periodic action

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 enables the detection of low concentrations, as low as 4.7 nM, with increased sensitivity by up to a factor of 4 compared to traditional amperometry, suitable for in vitro and in vivo applications.

Implementation Method 1

Electrons are first passed from glucose to the enzyme via enzymatic oxidation

Methodology Applied

Scientific EffectEnzymatic oxidation: Enzyme

Implementation Method 2

then to the working electrode through a redox mediator, such as oxygen (O2) or an Osmium (Os)-containing redox polymer

Methodology Applied

Scientific EffectRedox reaction: Redox Reactions

Implementation Method 3

providing the working electrode with a sensing element comprising an analyte-specific enzyme and a redox mediator, and carbon nanotubes

Methodology Applied

Scientific EffectElectron conduction: Conduction (electrical)

Implementation Method 4

In an amperometric measurement, the working electrode of the sensor is held at a constant potential (voltage) while the current flowing through the sensor is measured

Methodology Applied

Scientific EffectAmperometry:

Data Source

PatentEP4219735B1Method and apparatus for analyte detection using an electrochemical biosensor

Publication Date: 2026.04.01 ABBOTT DIABETES CARE INC

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Figure 3A

AI summary

A method for sensing an analyte utilizing a sensor having a working electrode, the method includes providing the working electrode with an analyte-specific enzyme and a redox mediator, providing the working electrode to the analyte, accumulating charge derived from the analyte reacting with the analyte-specific enzyme and the redox mediator for a set period of time, connecting the working electrode to circuit after the set period of time, and measuring the signal from the accumulated charge.