Optical Microbial Detection via Transmissive Culture Device
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Solution Overview
Problem
Traditional methods for detecting bacteria in samples rely on contrast between bacterial colonies and device components, which can be inhibitory and lack efficiency, necessitating the development of simpler, indicatorless detection methods that do not require inhibitory reagents and can automate the detection and enumeration of bacteria.
Innovation Solution
The use of culture devices with a base member, cover layer, and dry cold water-soluble gelling agent, configured to form a highly transmissive optical path, which allows for rapid detection of microorganisms by hydrating the growth area with a sample, incubating, illuminating, and observing for growth indications without the need for indicator reagents, and optionally employing contrast layers and imaging systems for enhanced detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional culture methods use indicator reagents to detect bacteria, then detection can be performed, but the indicator reagents have inhibitory effects on microorganism growth
Solution Approach 1:
The patent removes indicator reagents from the culture system entirely, extracting the harmful element while preserving detection functionality through alternative means (optical detection of colony formation, fluorescence from bacterial metabolites, or other endogenous signals). This eliminates the inhibitory effect while maintaining detection capability.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that does not involve direct chemical interaction between indicator reagents and bacteria. Instead, it uses optical intermediaries (light sources, detectors, filters) to detect bacterial presence through physical properties such as light scattering, absorption, or fluorescence emitted by bacterial colonies or their metabolites.
2Reliability
If traditional methods rely on contrast between bacterial colonies and device components, then detection is possible, but the method lacks efficiency and simplicity
Solution Approach 1:
The patent replaces manual visual inspection methods with automated optical detection systems. Light sources illuminate the culture medium and detectors automatically measure optical properties (transmittance, absorbance, fluorescence) to identify bacterial colonies, substituting mechanical/visual processes with automated optical-mechanical systems that increase throughput and efficiency.
Solution Approach 2:
The patent utilizes color changes or optical property changes that occur naturally during bacterial growth or metabolism, such as fluorescence emission from bacterial metabolites, changes in light scattering properties as colonies form, or pH-induced color changes in the medium. These inherent optical changes provide high-contrast signals that are easily detected by automated systems without requiring additional indicator reagents.
3Reliability
If manual detection methods are used to observe bacterial growth, then detection can be performed, but automated detection and enumeration is not achieved
Solution Approach 1:
The patent implements feedback loops where detectors continuously monitor optical properties of the culture medium, compare readings against reference values or thresholds, and automatically trigger detection algorithms. The system provides real-time feedback on bacterial presence and quantity, enabling automated enumeration and reducing manual intervention while maintaining high detection accuracy through continuous monitoring and data analysis.
Solution Approach 2:
The patent designs the culture system to be self-detecting, where bacterial colonies or their metabolites automatically generate detectable optical signals (fluorescence, light scattering, absorption) without requiring manual addition of indicators or manual observation. The system uses the bacteria's own metabolic activities or physical presence to create the detection signal, enabling fully automated detection and enumeration.
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 rapid, automated detection and enumeration of bacteria without inhibitory effects, providing high contrast and spatial resolution to distinguish microbial colonies, even when close together, and can detect the presence of microorganisms before visible colonies form.
Implementation Method 1
The culture device can be configured to form a highly transmissive optical path extending from the outermost first major surface to the outermost second major surface
Implementation Method 2
a dry cold water-soluble gelling agent disposed on the base member and/or the cover sheet
Implementation Method 3
illuminating the growth area with a light source
Implementation Method 4
detecting the scattering, absorbance or transmittance of light
Implementation Method 5
detecting the scattering, absorbance or transmittance of light
Data Source
AI summary
The disclosure provides culture devices and methods for a microorganism in a sample. The devices include a base member, a cover sheet, an adhesive layer coupled to the base member or the cover sheet, and a cold water-soluble gelling agent disposed on the base member; wherein the devices are substantially optically transmissive when the gelling agent is hydrated with a clear liquid. Methods of use include detecting or enumerating microorganisms. The methods further provide for detecting a microorganism by detecting the presence or size of an abiogenic gas bubble in a culture device.