NAD(P)-Dependent Dehydrogenase Biosensor Oxygen Interference

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional biosensors for detecting β-hydroxybutyrate in blood samples face issues with stability, sensitivity, and interference from co-existing species, leading to inaccurate and delayed detection of diabetic ketoacidosis, as they are not effective in measuring the dominant ketone body in blood.

Innovation Solution

A biosensor using a mediator previously considered an irreversible enzyme inhibitor, such as Meldola's Blue, in combination with NAD+ cofactor, is developed to provide a stable and sensitive response to β-hydroxybutyrate concentrations, even after long-term storage, allowing for accurate detection without enzyme inhibition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional biosensors use oxidase enzymes with oxygen or mediators like ferrocene, then the biosensors can detect analytes, but they are affected by oxygen during measurement and have stability issues

Engineering Contradiction:

Improvesensor stabilityVSAvoidoxygen interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a novel mediator compound that facilitates electron transfer between the dehydrogenase enzyme and the electrode without involving oxygen. This mediator enables the biosensor to detect β-hydroxybutyrate while being unaffected by oxygen interference, resolving the contradiction between sensor stability and oxygen sensitivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the oxygen-dependent oxidase enzyme system with an oxygen-independent dehydrogenase enzyme system that uses a synthetic mediator compound. This substitution eliminates the harmful oxygen interference while maintaining detection capability, improving both reliability and resistance to environmental factors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional biosensors detect ketone bodies, then they can monitor diabetes, but they only detect acetoacetate and not β-hydroxybutyrate, leading to delayed and inaccurate detection

Engineering Contradiction:

Improveketone body detection accuracyVSAvoiddetection delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the detection target from acetoacetate to β-hydroxybutyrate by selecting a dehydrogenase enzyme specific for this ketone body. This parameter change enables early detection of ketosis onset, improving measurement precision and eliminating detection delays associated with urine-based acetoacetate testing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a new detection system that copies the successful amperometric biosensor approach but applies it to β-hydroxybutyrate detection using dehydrogenase enzymes. This allows direct measurement of the dominant ketone body in blood, providing accurate and timely detection compared to conventional urine-based methods.

Inventive Principle:

Principle #26Copying

3Power

If biosensors use mediators that are irreversible enzyme inhibitors, then electron transfer is enhanced, but enzyme activity is inhibited

Engineering Contradiction:

Improveelectron transfer rateVSAvoidenzyme activity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent modifies the mediator's chemical structure to change its binding characteristics, allowing it to function as an effective electron transfer agent without irreversible inhibition of the dehydrogenase enzyme. This parameter change in mediator chemistry enables both high electron transfer rates and maintained enzyme activity, resolving the contradiction between power and reliability.

Inventive Principle:

Principle #35Parameter changes

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 a stable and sensitive response to β-hydroxybutyrate levels, enabling early and effective diagnosis of diabetic ketoacidosis with improved accuracy and reliability, even after extended storage periods.

Implementation Method 1

The use of dehydrogenase enzymes in biosensors... uses compounds as mediators for the recycling of cofactors used in the sensor

Methodology Applied

Scientific EffectElectron transfer:

Implementation Method 2

NAD(P)-dependent dehydrogenase enzymes... NAD+ cofactor

Methodology Applied

Scientific EffectRedox reaction: Redox Reactions

Data Source

PatentUS8500990B2Electrochemical biosensors based on NAD(P)-dependent dehydrogenase enzymes

Publication Date: 2013.08.06 NOVA BIOMEDICAL CORP

AI summary

A biosensor for measuring an analyte in a liquid sample includes a working electrode having a dispensed reagent thereon wherein the dispensed reagent contains an enzyme capable of catalyzing a reaction involving the analyte, a mediator that is considered an enzyme inhibitor, and an enzyme co-factor where the working electrode provides a stable and sensitive response even when the biosensor is stored at ambient conditions for a period of time selected from the group consisting of at least 3 months, 12 months and two years or more.