Fluorescent Bacterial Detection Device Using Composite Dyes
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Solution Overview
Problem
Current methods for determining the live and dead bacterial state of fungi in food products are time-consuming, limited in scope, and require high-magnification lenses, making them impractical for immediate and accurate assessment in food production and distribution settings.
Innovation Solution
A device with a measurement mechanism that includes a fungus base holding mechanism, excitation light irradiation using LEDs, and a CMOS image sensor for accurate imaging of fluorescent emissions, allowing for the differentiation of live and dead bacteria without the need for extensive cultivation or high-magnification viewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional cultivation methods are used to determine bacterial state, then determination accuracy can be achieved, but the process requires 24-48 hours which is too time-consuming for practical food distribution use
Solution Approach 1:
The patent applies preliminary action by pre-staining bacteria with fluorescent dyes (SYTO 9 and propidium iodide) before the determination process. This allows the staining to be completed in advance, so that when observation is needed, the bacteria are already prepared and can be immediately observed under appropriate excitation light, eliminating the 24-48 hour cultivation wait time while maintaining determination accuracy
Solution Approach 2:
The patent replaces the mechanical/biological cultivation process with an optical observation system. Instead of waiting for bacterial colonies to grow on culture media (mechanical/biological process), the invention uses fluorescent staining combined with optical microscopy or flow cytometry to directly observe and determine bacterial state, substituting a time-consuming biological process with a rapid optical detection method
2Loss of time
If fluorescent dyes are used to penetrate bacterial cells for immediate determination, then determination time is reduced, but fluorescent dye leaks easily from cells making light emission energy weak
Solution Approach 1:
The patent uses a composite staining approach by combining two fluorescent dyes (SYTO 9 and propidium iodide) that work together to differentiate live and dead bacteria. SYTO 9 penetrates all cells and provides green fluorescence, while propidium iodide penetrates only dead cells with compromised membranes and provides red fluorescence. This composite approach ensures strong, stable fluorescence emission from both live and dead bacteria without leakage issues, maintaining measurement precision while enabling rapid determination
3Measurement precision
If high magnification lenses are used to observe fluorescent bacteria, then determination accuracy improves, but the device becomes large in size and high in cost
Solution Approach 1:
The patent uses flow cytometry as an alternative copying method where bacterial cells are passed individually through a detection chamber and their fluorescent properties are measured by optical sensors. This creates an electronic copy/digital representation of bacterial characteristics without requiring physical magnification, enabling accurate determination with compact, cost-effective equipment
Solution Approach 2:
The patent transitions from two-dimensional optical microscopy observation to three-dimensional flow-based detection. By suspending bacteria in fluid and passing them through a detection chamber, the system captures fluorescent information from multiple angles and dimensions simultaneously using photodetectors, achieving high measurement precision without requiring high-magnification lenses or large optical paths
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 and accurate determination of live and dead bacterial states, reducing operational complexity and improving accuracy compared to conventional methods, facilitating better sanitation management in food production and distribution.
Implementation Method 1
fluorescent dye made of fluorescein or derivatives thereof penetrated in the cells of live bacteria absorbs excitation light with a specific wavelength of 480 nm and indicates strong fluorescence emission with a wavelength of 520 nm
Implementation Method 2
an imaging camera arranged above the fungus on the fungus base through a fixation frame
Data Source
AI summary
Provided is a device for determining the live/dead bacterial state, with which it is possible to ascertain the accurate state of live bacteria/dead bacteria via a captured image in a relatively easy operation with which ascertaining the state of a bacterial cell is more accurate than conventional methods. This device for determining the live/dead bacterial state comprises: a case body in which a measurement mechanism is housed; an opening/closing lid body that allows a fungus base insertion port formed in the case body to be opened and closed; and the measurement mechanism, which is housed in the case body and is configured to measure the number of bacteria. The measurement mechanism comprises: a fungus base holding mechanism that inserts and fixes a fungus base on which a bacterial cell collected from a specimen is placed; an excitation light irradiating mechanism configured so as to be capable of focusing and irradiating an excitation light toward the bacterial cell on the fungus base; an imaging camera disposed above the bacterial cell on the fungus base; and an XY-axes adjustment mechanism that minutely adjusts and moves, in the XY-axes, an XY stage supporting the fungus base holding mechanism and comprising two separately moving layers.