Sheath-Free Flow Cytometry Using LED Beam Trajectory Detection
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Solution Overview
Problem
Current hematology devices for counting and characterizing white blood cells are complex and costly due to the need for sheathing flows and multiple fluidic components, which lead to reagent wastage and measurement uncertainties, and fail to reliably differentiate between white blood cell subpopulations using impedance measurements alone.
Innovation Solution
A flow cytometry method that combines impedance and optical measurements without the use of sheathing flows, using a light-emitting diode to generate a beam larger than the orifice diameter to deduce particle trajectory information, allowing for selective data processing and characterization of particles based on their trajectory, thereby simplifying the device and reducing reagent consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sheathing flows are used to confine particles in the optical measurement zone, then measurement precision is improved, but device complexity increases and reagent consumption increases
Solution Approach 1:
The patent removes the sheathing flow system entirely from the device architecture. Instead of using complex fluidic components to generate and control sheathing flows, the invention relies on a simplified single-flow configuration where particles are naturally confined to the optical measurement zone through the interaction of the sample flow with the light beam, eliminating the need for additional fluidic inlets, micro-nozzles, and control mechanisms
Solution Approach 2:
The patent replaces the mechanical fluidic system (sheathing flows, micro-nozzles, fluidic components) with an optical-based particle confinement mechanism. The light beam itself serves to define the measurement zone, and particles are confined through their interaction with the optical field rather than through mechanical fluidic constraints, thereby simplifying the device structure
2Measurement precision
If sheathing flows are used to confine particles, then measurement precision is improved, but reagent consumption increases
Solution Approach 1:
The patent eliminates the sheathing flow system, which was consuming large volumes of diluent reagent. By removing this system, the device only processes the necessary sample volume without the additional reagent required for generating and maintaining sheathing flows, thereby reducing reagent consumption and waste production
Solution Approach 2:
The sample flow itself serves the dual function of transporting particles and defining the measurement zone through its interaction with the light beam. The particles are naturally confined to the optical measurement zone without requiring external sheathing flows, allowing the system to use reagent efficiently for its primary purpose of particle analysis rather than for fluidic control
3Adaptability or versatility
If impedance and optical measurements are performed in separate analysis cuvettes, then measurement capabilities are improved, but device complexity increases and measurement reliability decreases
Solution Approach 1:
The patent combines impedance and optical measurements into a single integrated analysis zone. The same flow channel serves as both the impedance measurement cuvette and the optical measurement cuvette, with electrodes positioned to detect impedance changes while a light beam passes through the same region for optical detection. This unified approach eliminates the need for separate cuvettes and data fusion algorithms, simplifying the device structure
Solution Approach 2:
The single flow channel is designed to perform multiple functions simultaneously: it serves as the measurement zone for both impedance and optical detection, and it naturally confines particles without requiring additional fluidic components. This multi-functional design eliminates the need for separate specialized cuvettes for each measurement type, reducing device complexity while maintaining measurement versatility
4Measurement precision
If multiple fluidic components are used for sheathing flows, then particle confinement is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the complex assembly of fluidic components required for generating sheathing flows. The device is manufactured with a simple flow channel and light source configuration, eliminating the need for precision assembly of multiple fluidic parts, micro-nozzles, and associated control mechanisms, thereby reducing manufacturing cost and complexity
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 approach results in a more economical, simpler device that maintains equivalent measurement quality, reducing reagent usage and device complexity while enabling accurate characterization and classification of white blood cells without the need for sheathing flows.
Implementation Method 1
generation, by means of a light-emitting diode, of a beam larger than the diameter of the orifice
Implementation Method 2
measurement of the change in electrical impedance generated by the passage of said particles contained in the fluid through the orifice tank
Data Source
Figure 1~2(b)
Figure 3(a)~4(b)
Figure 5(a)~5(b)
AI summary
The invention relates to a method and to a device used to carry out a flow cytometry method, preferably intended for, but not limited to, the counting and differentiation of white blood cells. More specifically, the invention relates to the field of simplified hematology devices with low operating costs. According to the invention, the method is characterised in that an impedance measurement technique is used to identify particles having a trajectory that has not passed through a predetermined optical measurement area so as to treat said particles selectively, thereby eliminating the use of sheath fluids in order to guide the particles toward the measurement area.