Total Internal Reflection Flow Cell for Imaging Cytometry
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Solution Overview
Problem
Conventional optical flow systems face inefficiencies in collecting light from rectangular flow cells with laser fan illumination, resulting in weak and variable particle fluorescence due to sensitivity to different optical paths and high autofluorescence from optical components.
Innovation Solution
A high aspect ratio rectangular glass flow cell is used to facilitate total internal reflections, with fluorescence measurement optics configured perpendicularly to the imaging and excitation optics, allowing light to reflect efficiently towards detectors, enhancing signal collection and reducing autofluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard light collection methods are used from a rectangular flow cell, then the system structure is simple, but the fluorescence signal is weak and varies greatly with particle position
Solution Approach 1:
The patent converts the harmful effect of light scattering and variable optical paths into a beneficial total internal reflection effect. By designing the flow cell with specific refractive index differences between the sample medium and glass walls, scattered light that would normally be lost is instead reflected back through the sample multiple times, enhancing fluorescence signal collection efficiency and uniformity across different particle positions.
Solution Approach 2:
The patent changes the optical parameters of the flow cell by selecting glass materials with specific refractive indices that create total internal reflection conditions. This parameter change transforms the optical behavior of light within the flow cell, converting random scattering into directed reflections that improve signal quality without requiring complex optical components.
2Object-generated harmful factors
If conventional flow cell configuration is used, then the optical components are simple, but autofluorescence from optical components is high
Solution Approach 1:
The patent extracts and removes the source of autofluorescence by eliminating conventional optical components (lenses, windows, mirrors) that are positioned in the excitation and emission paths. The flow cell is designed so that fluorescence is collected through total internal reflection at the glass-sample interfaces, eliminating the need for additional optical elements that would generate background autofluorescence.
3Measurement precision
If multiple optical components are used for fluorescence collection, then the collection efficiency is low, but the system is complex
Solution Approach 1:
The flow cell glass walls serve multiple functions: they contain the liquid sample, provide structural support, and act as total internal reflection surfaces for fluorescence collection. This multi-functionality eliminates the need for separate collection lenses and mirrors, achieving high collection efficiency with minimal optical components.
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 configuration significantly improves fluorescence signal integrity and sensitivity, enabling accurate and robust measurements of particles across a large particle position range, while reducing background fluorescence and allowing higher laser power usage.
Implementation Method 1
the flow chamber is configured to enable fluorescence propagation from the fluid within the channel to an edge of the flow chamber for enhanced light collection of the fluorescence
Implementation Method 2
a light source arranged to generate light scatter and/or fluorescence from particles
Data Source
AI summary
An imaging flow cytometry system and method which includes a flow chamber, fluorescence analysis and imaging optics, image capturing system, device to regulate fluid flow through the chamber, and backlighting generator. The flow cell is configured so as to enhance the fluorescence signal collection by the system with total internal reflections. The fluorescence collection optics are configured to enhance the collection of the fluorescence from the side of the flow cell and concentrate it on light detectors.