Fluorescent Soil Detection in Medical Instrument Washing
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Solution Overview
Problem
Human visual inspection for detecting residual bio-contaminants on medical devices and other articles is time-consuming, costly, prone to human error, and difficult in ambient light conditions, and existing optical detection methods using fluorescent dyes are limited by the need for ultraviolet light.
Innovation Solution
A soil detection system using optical excitation and luminescence, specifically a handheld scanning unit with a laser light source and dichroic beamsplitter, which emits blue light to excite a fluorescent agent like fluorescein, allowing for fluorescence detection in ambient lighting conditions through a digital camera sensor, providing a high signal-to-noise ratio and enabling accurate soil detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If human visual inspection is used to detect residual bio-contaminants, then the inspection can be performed in ambient light conditions, but the process is time-consuming and prone to human error
Solution Approach 1:
A fluorescent agent is introduced as an intermediary substance that binds to organic residues (soil) on articles. When exposed to blue light (450-490 nm), the fluorescent agent emits visible light, making the soil detectable in ambient lighting conditions without requiring ultraviolet black light. This mediator enables reliable detection while maintaining ease of operation in normal light environments.
2Measurement precision
If ultraviolet black light is used to excite fluorescent agents for soil detection, then soil can be detected with high contrast, but personnel cannot perform inspection in desirable ambient light conditions
Solution Approach 1:
The excitation wavelength parameter is changed from ultraviolet (traditional black light) to blue light in the 450-490 nm range. This parameter change allows the fluorescent agent to be excited by blue light sources that are compatible with ambient lighting conditions, while still producing sufficient fluorescence emission for sensitive soil detection. The blue light excitation maintains measurement precision while improving illumination compatibility.
3Measurement precision
If additional marking or rinse cycles are added to enable fluorescent detection, then accurate soil detection can be achieved, but the washing process becomes more complex and time-consuming
Solution Approach 1:
The fluorescent agent is designed to serve multiple functions: it acts as both a cleaning cycle component and a detection marker. The agent can be applied during existing wash or rinse cycles without requiring separate marking or detection cycles, thereby achieving accurate soil detection while avoiding additional process complexity. The same washing infrastructure is used for both cleaning and detection purposes.
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
Enables efficient and accurate detection of bio-contaminants in ambient light, reducing human error and operational costs, while maintaining compatibility with existing washing cycles without the need for additional marking or rinse cycles.
Implementation Method 1
The fluorescent agent binds to organic residues (e.g., proteins), and thus affixes to the soil to label the bio-contaminant... Absorbance of this ultraviolet (UV) light causes the fluorescent agent (e.g., a fluorophore such as fluorescein) to emit visible light (i.e., to be fluorescent)
Data Source
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AI summary
A method and apparatus for optical detection of residual soil on articles (such as medical instruments and equipment), after completion of a washing or a rinsing operation by a washer. A soil detection system provides an indication of soil on the articles by detecting luminescent radiation emanating from the soil in the presence of ambient light.