Osmium Complex Mediator for Oxygen-Independent Glucose Biosensors

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Solution Overview

Problem

Existing electrochemical biosensors for blood glucose measurement are influenced by oxygen partial pressure, temperature, and humidity, leading to measurement errors and instability over time, especially when storing and using sensors for extended periods.

Innovation Solution

An osmium complex-based electron transfer mediator that maintains a stable oxidation-reduction form for an extended time, unaffected by oxygen partial pressure, is used in an electrochemical biosensor, allowing for accurate glucose detection across a wide concentration range without significant performance changes due to environmental factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If FAD-GOx enzyme is used in the biosensor, then the sensor has excellent reaction selectivity to oxidize only glucose, but the measurement result becomes highly dependent on oxygen partial pressure in the blood sample

Engineering Contradiction:

Improveglucose detection selectivityVSAvoidoxygen partial pressure interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an electron transfer mediator (osmium complex) as an intermediary substance between the electrode and the enzyme. This mediator facilitates electron transfer from the enzyme active site to the electrode without requiring oxygen participation, thereby eliminating oxygen partial pressure interference while maintaining glucose detection selectivity through the enzyme's specific catalytic action.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the oxygen-dependent chemical reaction mechanism with an electrochemical mechanism mediated by the osmium complex. Instead of relying on oxygen diffusion and reaction with glucose, the system uses electrochemical electron transfer through the mediator, substituting the chemical reaction pathway with an electrochemical one that is independent of oxygen concentration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If high oxidation potential is applied to measure hydrogen peroxide oxidation current, then the measurement can be performed, but other oxidative substances like ascorbic acid and uric acid are also oxidized causing severe measurement errors

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidglucose measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The osmium complex acts as a selective intermediary that mediates electron transfer at a controlled potential. This mediator enables the detection of glucose oxidation products at a lower potential than conventional methods, creating a potential window that selectively detects glucose-related signals while avoiding the oxidation of other substances like ascorbic acid and uric acid that occur at higher potentials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operating potential parameter from high oxidation potential to a lower, controlled potential facilitated by the osmium complex mediator. This parameter change shifts the detection window to a range where glucose oxidation products are detectable while other oxidative substances remain unaffected, thereby improving measurement precision.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional electron transfer mediators like Ferricyanide are used, then the sensor is inexpensive and has good reactivity, but the sensor performance deteriorates due to temperature and humidity and shows measurement errors from interfering substances

Engineering Contradiction:

Improvecost and reactivityVSAvoidstability against temperature and humidity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameter of the electron transfer mediator from conventional Ferricyanide to an osmium complex with different chemical properties. This parameter change results in a mediator that maintains stable redox potential and electrochemical activity across a wider temperature and humidity range, while also providing resistance to oxidation by interfering substances, thereby improving reliability without sacrificing cost-effectiveness.

Inventive Principle:

Principle #35Parameter changes

4Duration of action of stationary object

If the biosensor is stored for long periods, then the sensor can be used later, but the background current changes and glucose detection accuracy decreases

Engineering Contradiction:

Improvestorage durationVSAvoidglucose detection accuracy

Core Design Contradiction:

Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent employs the osmium complex mediator which maintains its electrochemical activity and stable redox state throughout extended storage periods. The mediator's stable chemical structure and resistance to degradation allow the sensor to retain its calibration and detection accuracy even after long-term storage, effectively extending the usable life of the sensor without requiring frequent replacement.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS10890557B2Electrochemical biosensor

Publication Date: 2021.01.12 I SENS INC

AI summary

The present disclosure relates to an electron transfer mediator comprising the osmium complex or a salt thereof, a reagent composition for an electrochemical biosensor, and an electrochemical biosensor, where the osmium compound or its salt maintains a stable oxidation-reduction form for an extended time period, a capacity to react with oxidoreductase being capable of performing the redox reaction of the target analytes, and no effect of oxygen partial pressure.