Dual Migrating Indicator for Sterilization Monitoring

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Solution Overview

Problem

Current sterilization indicators are costly, require multiple test strips for different sterilization conditions, and lack precise control over temperature and time parameters, leading to potential misinterpretation of sterilization efficacy.

Innovation Solution

A dual indicator configured with two pass zones that can indicate acceptable sterilization for two different conditions, using a thermally conductive base element, indicator chemical composition, wicking material, film layer, and adhesive layers to visually confirm sterilization at specific temperatures and times, reducing the need for multiple indicators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate sterilization indicators are used for different sterilization conditions, then each indicator can be optimized for its specific condition, but the device complexity and cost increase

Engineering Contradiction:
Improvesterilization monitoring accuracyVSAvoidnumber of different indicators
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sterilization indicator is designed with multiple pass zones (first pass zone and second pass zone) that can detect and indicate different sterilization conditions (e.g., 121°C for 15 minutes and 132°C for 4 minutes). This multi-functional design allows a single indicator to replace multiple separate indicators, reducing device complexity while maintaining reliability for various sterilization protocols

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The indicator is segmented into distinct functional zones: a first pass zone for detecting lower temperature/longer time sterilization and a second pass zone for detecting higher temperature/shorter time sterilization. Each zone contains specific indicator materials that respond to different thermal conditions, enabling differentiated monitoring within a single integrated device

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If spore strips are used for sterilization control, then accurate sterilization verification is achieved, but the cost and time for processing increase

Engineering Contradiction:
Improvesterilization verification accuracyVSAvoiddelay between processing and control data
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The indicator performs self-indication through visual changes in color or appearance when exposed to sterilization conditions. The indicator materials automatically respond to temperature and time parameters, producing visible results immediately after the sterilization cycle without requiring external laboratory processing or incubation periods

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sterilization indicator is designed as a disposable, low-cost item that provides immediate results. Unlike spore strips that require laboratory incubation and analysis, the indicator gives instant visual feedback, eliminating the need for expensive laboratory processing while maintaining adequate verification accuracy

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If chemical sterility indicators are used, then cost is reduced compared to spore strips, but temperature and time parameter control is insufficient

Engineering Contradiction:
Improvecost effectivenessVSAvoidtemperature and time parameter control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Different regions of the indicator (first pass zone and second pass zone) contain different indicator materials with specific thermal and temporal response characteristics. Each zone is locally optimized to respond to specific sterilization conditions, providing precise parameter control while maintaining overall cost-effectiveness

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The indicator utilizes materials that change physical or chemical properties (such as color, fluorescence, or luminescence) in response to specific temperature and time parameter changes during sterilization. These parameter-dependent material transformations enable precise monitoring of sterilization conditions at a lower cost than biological methods

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 dual indicator effectively replaces two Class 6 sterilization indicators, providing accurate and cost-effective monitoring for multiple sterilization conditions while ensuring precise control over temperature and time parameters, thus enhancing user confidence in sterilization processes.

Implementation Method 1

a wicking material positioned at least in part in contact with the indicator chemical composition

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a base element formed from a thermally conductive material

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9360464B2Dual migrating indicator
Publication Date: 2016.06.07 AMERICAN STERILIZER CO

AI summary

An indicator for a sterilization process is configured to function for two different sterilization conditions. The indicator includes two pass zones to indicate whether an acceptable sterilization has occurred after a sterilization process at a first condition of after a sterilization process at a second condition.