Microfluidic Cassette Combining Optical and Electrical Particle Detection
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Solution Overview
Problem
Current methods for characterizing particles in a fluid carrier medium, such as optically-based and electrically-based data acquisition, are either tedious and prone to errors or limited in their ability to provide comprehensive information about particle count, size, type, and viability, lacking a combined approach for accurate and efficient analysis.
Innovation Solution
An apparatus and method that combines optically-based and electrically-based data acquisition by using a microfluidic cassette to obtain both optical and electrical signals, allowing for the characterization of particles in terms of count, size, type, and viability, with the optically-based signal extracted from an optical-interrogation location and the electrical signal used to determine fluid boundary locations and particle characterization, displayed on a user interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optically-based data acquisition is used to characterize particles, then particle information can be obtained, but the process is tedious and prone to errors
Solution Approach 1:
The patent combines optical detection and electrical impedance detection into a single integrated system. The optical detector captures light scattering signals from particles, while the electrical impedance detector measures impedance changes as particles pass through the aperture. By merging these two detection methods, the system achieves both high measurement precision through multiple characterization parameters and high productivity through automated simultaneous detection of multiple particles
Solution Approach 2:
The system performs multiple functions simultaneously: optical detection provides particle size and morphology information, while electrical impedance detection provides particle volume and conductivity information. This multi-functional approach eliminates the need for separate manual counting and characterization processes, thereby improving both accuracy and efficiency
2Productivity
If electrically-based data acquisition is used to detect particles, then particle detection can be performed, but comprehensive information about particle count, size, type, and viability is limited
Solution Approach 1:
The patent merges electrical impedance detection with optical detection to compensate for the limitations of each individual method. Electrical detection provides rapid particle detection and counting, while optical detection adds comprehensive information about particle size, morphology, and optical properties, thereby recovering the information loss inherent in electrical-only detection
Solution Approach 2:
The system uses light scattering as an intermediary mechanism to extract additional particle information. When particles pass through the aperture, they scatter light in characteristic patterns that provide information about particle size, shape, and composition, supplementing the electrical impedance data with comprehensive particle characterization
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 combined approach enables accurate and efficient characterization of particles, providing comprehensive data on particle count, size, type, and viability, reducing errors and improving analysis efficiency compared to traditional methods.
Implementation Method 1
obtain an optically-based signal related to optical particle characterization of a plurality of particles... The optically-based signal is typically extracted from an optical-interrogation location disposed along the channel in the cassette
Implementation Method 2
Exemplary optically-based interrogation structure may include a light source oriented to emit light energy to impinge through a sufficiently transparent window of a cassette, an optional focusing lens arrangement, and an image sensor oriented to receive the transmitted light
Implementation Method 3
measuring impedance deviation caused by particles flowing through a small aperture between two containers of electrically conductive fluid... particles causing a change in electric impedance as they occlude a portion of the aperture
Implementation Method 4
Pioneering work in particle detection by measuring impedance deviation caused by particles flowing through a small aperture between two containers of electrically conductive fluid is disclosed in U.S. Pat. No. 2,656,508 to W. H, Coulter. Coulter's name is now associated with the principle of particles causing a change in electric impedance as they occlude a portion of the aperture
Implementation Method 5
a removable microfluidic cassette to obtain an optically-based signal related to optical particle characterization of a plurality of particles carried by a fluid that can be urged to move through a channel in the cassette
Data Source
AI summary
An apparatus for, and a method of, characterizing a plurality of particles carried by a fluid that can be urged to move through a channel in a microfluidic cassette by combining data analysis of a first signal that is optically-based, and data analysis of a second signal that is electrically-based. Optically-based information is typically obtained by a digital image sensor. Electrically-based information can be obtained by direct measurement of impedance; sometimes in an arrangement operating under the Coulter principle. Data provided by exemplary characterization includes at least one of: volumetric cell count; viability percentage or ratio; particle type; and a particle size histogram.