Confocal Particle Detection Without Sheath Fluid
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Solution Overview
Problem
Conventional flow cytometry systems rely heavily on a stable sheath fluid to maintain particle alignment and focus, making setup and maintenance labor-intensive and complex, and resulting in inaccurate detection data from out-of-focus particles.
Innovation Solution
An enhanced detection system that uses position detection to differentiate between in-focus and out-of-focus particles, allowing for selective data collection and disregard of out-of-focus data, eliminating the need for sheath fluid and utilizing confocal microscopy and peripheral detectors to determine particle positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sheath fluid is used to maintain particle alignment and focus, then particle positioning accuracy is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent removes the sheath fluid component from the system entirely. Instead of using fluid dynamics to maintain particle alignment, the invention uses optical focusing methods where particles are imaged through a focal point, and only in-focus particles are detected. This extraction of the sheath fluid subsystem eliminates the associated complexity while maintaining measurement precision through optical sectioning.
Solution Approach 2:
The patent replaces the mechanical/fluidic particle alignment system (sheath fluid flow) with an optical system. Particles are focused optically through a focal point rather than being aligned hydrodynamically. The detection system uses confocal microscopy principles where only light from the focal plane is collected, substituting fluid-based positioning with light-based selection.
2Measurement precision
If sheath fluid is used to guide particles in single-file arrangement, then detection accuracy is improved, but setup and maintenance labor increases
Solution Approach 1:
The patent eliminates the sheath fluid delivery system, which is a major source of setup and maintenance labor. Without sheath fluid, there are no pumps, flow controllers, or fluid path components requiring maintenance. The system achieves detection accuracy through optical confocality rather than hydrodynamic focusing, removing the labor-intensive fluid management subsystem.
3Measurement precision
If position detection is implemented to differentiate in-focus and out-of-focus particles, then data accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the particle detection function with the optical focusing function into a single confocal detection system. The same optical path that focuses particles also detects their position. In-focus particles produce strong signals while out-of-focus particles produce weak or no signals, allowing position-based data filtering without adding separate detection subsystems. This merging maintains data accuracy while avoiding additional complexity.
Solution Approach 2:
The optical system automatically differentiates between in-focus and out-of-focus particles through the principles of confocal microscopy. The detection system inherently provides position information through signal intensity variations based on focal position, without requiring external positioning sensors or additional complexity. The system self-services the position detection function through its fundamental optical design.
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 enhances data accuracy, simplifies system operation, and enables analysis of environmental samples with reduced complexity and power requirements, allowing for compact, user-friendly, and adaptable cytometric measurements.
Implementation Method 1
particles are aligned and carried along ideally in a single file arrangement within a stream of clear fluid, also known as a sheath fluid, to pass before one or more beams of light in an sensing region for subsequent detection of various parametric characteristics
Implementation Method 2
detection of various parametric characteristics to classify, categorize, quantify or otherwise detect one or more aspects of the particles
Data Source
AI summary
An enhanced detection system can eliminate use of a sheath fluid by selecting which particles that pass through an sensing region to detect parametric characteristics thereof based upon position of each particle while it is in a sensing region relative to one or more predetermined positions, such as an in-focus position relative to one or more light beams directed into the sensing region, to enhance accuracy and robustness of particle parametric characteristics detection.