Biological Indicator Fluorescence Readout for Steam Sterilization
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Solution Overview
Problem
Existing biological indicators for sterilization processes are costly, time-consuming, and prone to false positives due to reliance on enzymatic reactions and genetically engineered microorganisms, requiring complex procedures and specialized equipment.
Innovation Solution
A self-contained biological indicator using microbial spores, exogenous sensor proteins, fluorophores, and a culture medium, which relies on immediate fluorescence and colorimetric tests to determine sterilization efficacy without enzymatic reactions, reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If genetically engineered microorganisms or enzymatic reactions are used as biological indicators, then the ability to detect sterilization efficacy is improved, but the cost, time consumption, and complexity of the procedure increase
Solution Approach 1:
The patent extracts the detection function from complex biological systems (genetically engineered microorganisms) and implements it using simple protein-fluorophore interactions. The indicator comprises a protein that changes conformation upon sterilization, causing a fluorophore to transition from a non-fluorescent to fluorescent state, eliminating the need for complex genetic engineering while maintaining detection reliability
Solution Approach 2:
The patent employs simple, inexpensive protein-fluorophore conjugates instead of costly genetically engineered microorganisms. These indicator proteins are stable, easy to manufacture, and provide reliable detection without requiring complex maintenance or specialized equipment, making the system more accessible and cost-effective
2Reliability
If enzymatic activity tests are performed after sterilization, then sterilization efficacy can be determined, but the incubation time and resource expenses increase significantly
Solution Approach 1:
The patent performs the detection action immediately after sterilization by measuring fluorescence intensity, eliminating the need for prolonged incubation periods required by enzymatic tests. The fluorophore-protein interaction occurs rapidly and can be measured directly, reducing the detection time from hours to minutes while maintaining accuracy
Solution Approach 2:
The patent replaces the biochemical enzymatic reaction system with an optical fluorescence detection system. Instead of measuring enzymatic activity that requires incubation, the system uses fluorescence intensity measurements that provide immediate results, substituting a time-consuming biochemical process with a rapid optical measurement
3Reliability
If enzymes are used as biological indicators, then sterilization can be detected, but false positives increase due to enzyme instability
Solution Approach 1:
The patent creates a simplified copy of the biological detection principle using protein-fluorophore interactions that mimic the conformational change detection of enzymatic tests but without the instability of enzymes. The fluorophore-linked protein provides a stable, reproducible signal that correlates with sterilization efficacy without suffering from enzyme degradation or false positives
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
Provides rapid and reliable results with immediate fluorescence detection and extended readout confirmation, minimizing handling and equipment requirements, thus reducing time and cost while ensuring accurate sterilization assessment.
Implementation Method 1
employing immediate fluorescence and colorimetric tests to determine sterilization efficacy
Implementation Method 2
leveraging changes in protein structure and fluorescence intensity to confirm sterilization effectiveness
Data Source
AI summary
The invention relates to a biological indicator for determining the efficacy of a steam or heat sterilization process, and its method. The biological indicator comprises microbial spores (a), at least one sensor protein exogenous to the microbial spores (b), one fluorophore (c), and a culture medium (d). The invention also refers to the method of use of this biological indicator. This method consists of (a) placing the biological indicator along with a target material to be steam or heat sterilized within a steam or heat sterilizer, (b) carrying out a steam or heat sterilization process, (c) placing the biological indicator in a an incubator, (d) screening the biological indicator for immediate detectable changes in fluorescence intensity, while incubating the biological indicator in the incubator, (e) determining the efficacy of the steam or heat sterilization process based on the screening carried out during step d), (f) extending the incubation of the biological indicator obtained in step d), (g) screening the incubated biological indicators obtained in step e) for an optically detectable color change, and (h) determining the efficacy of the steam or heat sterilization process, according to optically detectable changes obtained in step g).