Fluorescence Detection System With Decoupled Optical Channels
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Solution Overview
Problem
Current fluorescence detection systems for microfluidic diagnostic assays are hindered by instability due to photoquenching, thermo-convection, and interference from bubbles, requiring expensive confocal optics and struggling with assay validation and portability, especially in remote or resource-limited settings.
Innovation Solution
A compact fluorescence detection instrument with dual optical channels, decoupled excitation and emission optics, and a scanning detector head with autonomous signal processing, optimized for use with disposable microfluidic cartridges, featuring a floating stage and pneumohydraulic systems for improved alignment and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If confocal optics are used to improve signal detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the detection function from a complex confocal optical system and implements it using a simplified optical path with separate excitation and emission channels. The excitation source and detector are positioned at different locations, eliminating the need for complex confocal optics while maintaining detection precision through strategic optical component placement.
Solution Approach 2:
The optical system is segmented into distinct excitation and emission channels with separate optical paths. This segmentation allows each channel to be optimized independently, reducing overall system complexity while improving signal-to-noise ratio by preventing excitation light from directly reaching the detector.
2Measurement precision
If confocal optics are used to improve signal detection, then measurement precision is improved, but the instrument becomes less portable
Solution Approach 1:
The patent removes the heavy and complex confocal optical components and replaces them with a lightweight optical system using standard lenses and filters. The simplified optical path eliminates the need for precision confocal scanning mechanisms, significantly reducing instrument weight and improving portability for point-of-care applications.
3Reliability
If conventional optical systems are used, then signal detection is achieved, but photoquenching and thermo-convection cause instability
Solution Approach 1:
The patent introduces an intermediary optical path that physically separates the excitation and emission light paths. This intermediary approach prevents direct interaction between excitation light and the detector, reducing photoquenching effects. The separate optical channels also minimize thermal interference by isolating the excitation source from the detection region.
Solution Approach 2:
The optical system is divided into separate excitation and emission channels with distinct optical paths. This segmentation isolates the harmful effects of excitation light (photoquenching and thermal convection) from the detection region, improving signal stability by preventing these interfering factors from reaching the detector.
4Device complexity
If simple optical systems are used to reduce cost, then device complexity is reduced, but cross-talk between fluorophores increases
Solution Approach 1:
The patent applies local quality optimization by using wavelength-specific optical filters and dichroic mirrors at critical points in the optical path. These localized spectral separation elements enable simple optical systems to resolve multiple fluorophore emissions by selectively transmitting or blocking specific wavelength ranges, preventing cross-talk while maintaining system simplicity.
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
Enhances signal-to-noise ratio, reduces noise interference, and enables robust, portable, and cost-effective molecular diagnostics, facilitating broader access to molecular testing in remote locations by improving sensitivity and reducing cross-talk between fluorophores.
Implementation Method 1
a fluorescent probe or fluorophore absorbs light having a wavelength or range of wavelengths and becomes excited; and the fluorophore then emits a fluorescent signal
Implementation Method 2
A dichroic beam splitter or band-pass filter, or combination thereof, is then used to separate the fluorescent signal from other light
Implementation Method 3
The sensor is often a photodiode, and generates an electrical signal that can be used to score the assay
Data Source
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AI summary
Disclosed is a compact, microprocessor-controlled instrument for fluorometric assays in liquid samples, the instrument having a floating stage with docking bay for receiving a microfluidic cartridge and a scanning detector head with on-board embedded microprocessor operated under control of a ODAP daemon resident in the detector head for controlling source LEDs, emission signal amplification and filtering in an isolated, low noise, high-gain environment within the detector head. Multiple optical channels may be incorporated in the scanning head. In a preferred configuration, the assay is validated using dual channel optics for monitoring a first fluorophore associated with a target analyte and a second fluorophore associated with a control. Applications include molecular biological assays based on PCR amplification of target nucleic acids and fluorometric assays in general, many of which require temperature control during detection.