Flow Cytometry Signal Detection Using Intensity Modulation
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Solution Overview
Problem
Current flow cytometry systems face challenges in efficiently detecting and separating fluorescent signals from multiple excitation light sources due to complex optics requirements, sensitivity issues, and limitations in distinguishing fluorescent molecules with overlapping emission spectra, especially when multiple excitation sources are used simultaneously.
Innovation Solution
A system and method utilizing a flow channel with spatially separated optical interrogation zones, where a non-modulating excitation source provides a constant light intensity to one zone and a modulating excitation source provides intensity-modulated light to another zone, allowing for the detection of signal components from each zone using a detector subsystem and processor for de-modulation and signal component determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple excitation light sources are used simultaneously to excite fluorescent molecules, then the ability to detect multiple fluorescent signals is improved, but the complexity of optical separation and detection systems increases
Solution Approach 1:
The patent applies periodic action by intensity-modulating one or more excitation light sources at specific frequencies. This allows the system to distinguish between signals from different excitation sources through frequency discrimination, eliminating the need for complex optical separation systems while maintaining the ability to detect multiple fluorescent signals simultaneously
Solution Approach 2:
The patent changes the intensity parameter of excitation light sources over time through modulation. By varying the intensity at different frequencies, the system can differentiate between signals from multiple excitation sources using the same detection optics, thereby reducing system complexity while preserving multi-signal detection capability
2Adaptability or versatility
If multiple excitation light sources are used simultaneously, then the flexibility of fluorochrome selection is improved, but the ability to separate and detect overlapping fluorescent spectra deteriorates
Solution Approach 1:
The patent uses periodic intensity modulation of excitation light sources at distinct frequencies. This allows the detection system to resolve overlapping fluorescent spectra by identifying the modulation frequency of each signal, thereby maintaining measurement precision while enabling flexible fluorochrome selection
Solution Approach 2:
The patent changes the intensity parameter of excitation light sources in a time-dependent manner through modulation. This parameter change enables the system to distinguish between overlapping spectra from different fluorochromes excited by different sources, preserving spectral resolution while expanding fluorochrome selection flexibility
3Measurement precision
If intensity-modulated excitation light sources are used, then the ability to distinguish signals from different zones is improved, but the system complexity increases
Solution Approach 1:
The patent applies periodic intensity modulation to excitation light sources targeting different optical interrogation zones. The modulation frequencies serve as unique identifiers for each zone, allowing simple detection electronics to distinguish signals from different zones without increasing overall system complexity
Solution Approach 2:
The patent replaces complex mechanical or optical switching mechanisms with electronic intensity modulation of light sources. This substitution maintains the ability to distinguish signals from different zones while reducing mechanical complexity and improving system reliability
4Productivity
If spatially separated optical interrogation zones are used, then the ability to detect multiple signals simultaneously is improved, but the requirement for precise beam alignment and separation increases
Solution Approach 1:
The patent applies periodic intensity modulation to excitation light sources in spatially separated zones. This allows the system to detect multiple signals simultaneously through frequency discrimination at the detector, reducing the stringent alignment and separation requirements while maintaining high productivity
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 simplifies the detection process, reduces system complexity, improves signal-to-noise ratio, and enables effective detection of fluorescent signals from multiple excitation sources without the need for precise synchronization or high-frequency multiplexing, while minimizing interference and crosstalk between signals.
Implementation Method 1
a modulating excitation source that directs a light beam of a second wavelength with an intensity modulated over time at a modulating frequency onto a second of the optical interrogation zones... to induce the emission of modulated light from at least two spatially separated optical interrogation zones
Implementation Method 2
a detector subsystem that detects the emitted light and converts the detected emitted light into electrical signals
Data Source
AI summary
A system for detecting signal components of light induced by multiple excitation sources including: a flow channel including at least two spatially separated optical interrogation zones; a non-modulating excitation source that directs a light beam of a first wavelength at a near constant intensity onto a first of the optical interrogation zones; a modulating excitation source that directs a light beam of a second wavelength with an intensity modulated over time at a modulating frequency onto a second of the optical interrogation zones; a detector subsystem comprising a set of detectors configured to detect light emitted from particles flowing through the at least two optical interrogation zones and to convert the detected light into a total electrical signal; and a processor that determines signal components from the light detected from each of the optical interrogation zones.