Particle Counting in Laminar Flow via Digital Imaging
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Solution Overview
Problem
Current cell imaging and counting systems for low concentrations of target particles in large volumes of fluid face challenges such as high cost, unsatisfactory sensitivity, slowness, large size, insufficient spectral and/or spatial resolution, and labor-intensive preparation steps, making them unsuitable for applications like bioterrorism defense, food and water quality control, and clinical detection.
Innovation Solution
A novel integrated system comprising an imaging device, illuminator, flow channel, image processing means, counting means, and control means that adjusts apparatus parameters and signal processing in real-time based on estimated particle density, allowing for high throughput imaging-based enumeration of specific particles in translucent or transparent flowing liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow cytometry with sheath/core flow arrangement is used to achieve precision photometric measurements, then measurement precision is improved, but device complexity and cost increase due to requiring concentric cylindrical streams and laser illumination
Solution Approach 1:
The patent extracts the essential function of particle illumination and imaging from the complex sheath/core flow arrangement. By using a simple transparent tube with direct imaging of particles in the flow stream, the system removes unnecessary components (concentric flow channels, precise alignment mechanisms) while maintaining the ability to detect and count particles effectively
Solution Approach 2:
The patent uses digital imaging to create a visual record of particles in the flow, replacing the need for complex photometric measurement systems. The imaging device captures particle images that can be analyzed computationally, providing a simpler alternative to traditional optical measurement approaches
2Measurement precision
If small bore core flow is used to reduce flow diameter for precision measurements, then measurement precision is improved, but reliability deteriorates due to frequent clogging
Solution Approach 1:
The patent changes the flow regime parameters by using larger diameter transparent tubes instead of small bore flows. This parameter change allows particles to flow through without clogging while still enabling imaging-based detection and counting, thus maintaining reliability while achieving measurement goals through digital imaging rather than precision photometry
3Measurement precision
If flow cytometry with fluorescent labeling is used to identify specific cells, then measurement precision is improved, but ease of operation deteriorates due to labor-intensive preparation steps
Solution Approach 1:
The patent enables particles to be detected and counted based on their inherent optical properties or simple staining, without requiring complex fluorescent labeling procedures. The imaging system automatically captures and analyzes particle images, reducing the need for manual sample preparation steps involving antibody labeling and fluorescent marker attachment
4Device complexity
If conventional imaging systems are used to count particles in large volumes, then device simplicity is improved, but measurement precision deteriorates due to insufficient spectral and spatial resolution
Solution Approach 1:
The patent transitions from point-by-point photometric measurement to two-dimensional digital imaging of the entire flow cross-section. This dimensional change allows simultaneous capture of multiple particles across the flow, providing both spatial information (particle positions, sizes) and enabling spectral analysis through digital image processing, thus improving measurement precision while maintaining system simplicity
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
This system enables high sensitivity and cost-effective detection and identification of target particles over a wide dynamic range of densities, reducing operational costs and improving efficiency compared to existing technologies.
Implementation Method 1
A beam of illumination is used to excite fluorescence from target particles in the flow stream
Data Source
AI summary
An invention is described which allows measurement of the concentration of fluorescent particles in a flowing (laminar) fluid by imaging the flow with a video camera. A beam of illumination is used to illuminate the target particles. Imaging optics are arranged to view the focal plane to form an image of the multiple fluorescent sample particles in the flow stream; a camera records the image formed by the imaging optics, and a counting algorithm enumerates the particles. Operational parameters of the system are adjusted according to an initial estimate of particle density, for example flow rate, exposure time, and sampling interval. In addition, the counting algorithm is selected according to the estimated particle density.