Gel-Stabilized Biosensor Extends Enzyme Operational Lifetime

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Solution Overview

Problem

Enzyme-based biosensors face rapid deactivation issues due to storage conditions and exposure to deactivating compounds, limiting their operational life and commercial viability, especially in portable and wearable devices.

Innovation Solution

A biosensor design incorporating a crosslinked Sodium Polyacrylate gel to stabilize alcohol oxidase enzymes, preventing deactivation by silver/silver chloride, and using a dialysis membrane to filter out destabilizing agents, while maintaining enzyme activity for extended periods without chemical modification of the enzymes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If enzyme is fully hydrated for continuous measurement, then sensor can continuously measure alcohol presence, but enzyme deactivates after 24 hours

Engineering Contradiction:

Improvecontinuous measurement capabilityVSAvoidenzyme operational lifetime

Core Design Contradiction:

Ease of operationVSDuration of action of moving object

Solution Approach 1:

A gel matrix is introduced as an intermediary substance between the enzyme and the aqueous environment. The gel allows controlled water penetration and enzyme hydration while physically restricting complete enzyme deactivation, thereby extending operational lifetime during continuous measurement

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The physical state of water is changed from free liquid to gel-bound water, and the enzyme is transitioned from fully hydrated to gel-stabilized hydrated state. This parameter change in the hydration environment extends enzyme stability while maintaining continuous measurement capability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If enzyme is refrigerated or frozen for storage, then shelf life is extended, but sensor cannot be used more than once after taking out of storage

Engineering Contradiction:

Improveshelf lifeVSAvoidreusability after storage

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The storage and operational states are segmented into distinct phases: a stable dry storage phase and a controlled hydration phase. The gel matrix enables the enzyme to remain stable in dry storage while allowing controlled hydration for extended operational use, separating the requirements for shelf life and reusability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gel matrix is pre-prepared and integrated into the sensor structure before use, creating a ready-to-hydrate system. This preliminary preparation allows the enzyme to be rapidly activated upon contact with moisture while maintaining stability during storage, enabling multiple uses after storage

Inventive Principle:

Principle #10Preliminary action

3Duration of action of stationary object

If crosslinkers like aldehydes are used to improve enzyme stability, then longevity of sensing device is improved, but biocatalysts are inhibited or deactivated

Engineering Contradiction:

Improvesensing device longevityVSAvoidenzyme activity

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The gel matrix acts as a sacrificial protective component that can be easily replaced. Instead of modifying the expensive enzyme with crosslinkers, the gel provides physical protection and stability, allowing the enzyme to remain unmodified and fully active while extending device longevity through gel replacement

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If disposable cartridges are used for enzymatic sensors, then rapid enzyme deactivation is bypassed, but cost increases due to expensive cartridges

Engineering Contradiction:

Improveenzyme activity maintenanceVSAvoidcost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The gel matrix provides self-healing and self-stabilizing properties to the enzyme system. The gel protects the enzyme from deactivation mechanisms, allowing the same enzyme preparation to be used multiple times across different storage and usage cycles, eliminating the need for disposable cartridges while maintaining enzyme activity

Inventive Principle:

Principle #25Self-service

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 solution extends the operational life of enzyme-based biosensors from a few hours to multiple days, maintaining enzyme activity and stability even in the presence of destabilizing agents like silver/silver chloride, without increasing enzyme amounts or affecting sensor performance.

Implementation Method 1

a gel-based matrix for extending biocatalyst turnover lifetime

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

protects a sensitive biocatalyst from toxic or deactivating compounds

Methodology Applied

Scientific EffectMolecular exclusion: Molecular Sieve

Data Source

PatentUS20240215877A1A gel-based matrix for extending biocatalyst turnover lifetime

Publication Date: 2024.07.04 MILO SENSORS INC

AI summary

A device for maintaining functionality in a device reliant on active biocatalysts. A sensor has a biological catalyst, a buffered gel, and a detector component. The gelling component of the buffered gel can be adjusted to function as a barrier or semi-permeable membrane to keep the enzyme active longer. Experimental results show that the invention can sustain device activity for at least 5 days, which is normally only active for up to 1 day.