Optical Detection System Using Curved Microfluidic Channels
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Solution Overview
Problem
Conventional optical detection systems are too expensive and complex for use by non-technical personnel, and when made more affordable, they often sacrifice sensitivity, leading to inaccurate results due to high background interference in membrane-based assay devices.
Innovation Solution
An optical detection system with a chromatographic medium positioned between an illumination source and a detector, where the source and detector are positioned close to the assay device to enhance sensitivity and signal-to-noise ratio, using electroluminescent devices for diffuse illumination to reduce reliance on external optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional optical detection systems are made more affordable by reducing complexity, then cost and device complexity decrease, but sensitivity and signal-to-noise ratio deteriorate
Solution Approach 1:
The patent transitions from conventional lateral flow detection to vertical flow detection through a microfluidic channel with a curved bottom surface. This dimensional change in fluid flow path enables the formation of a concentrated analyte band at the detection zone, significantly improving signal-to-noise ratio and detection sensitivity while maintaining system simplicity and affordability
Solution Approach 2:
The patent modifies the physical parameters of the microfluidic channel, specifically creating a curved bottom surface with a radius of curvature between 0.5-5mm. This parameter change in the channel geometry causes centrifugal force to concentrate the analyte band vertically, enhancing detection sensitivity without increasing system complexity or cost
2Measurement precision
If distance between illumination source and detector is reduced to less than 5mm, then signal-to-noise ratio and sensitivity improve, but device miniaturization becomes more challenging
Solution Approach 1:
The patent integrates the illumination source and detector into a single handheld reader unit that can be positioned close to the assay device. This merging of components into one portable unit achieves the required <5mm distance for high signal-to-noise ratio while maintaining manageable device size through component integration
Solution Approach 2:
The patent introduces a microfluidic channel with curved geometry as an intermediary structure that concentrates the analyte band vertically. This intermediary mechanism enhances the detection signal by concentrating analytes at the detection zone, allowing the use of smaller, less sensitive illumination and detection components while maintaining high signal-to-noise ratio
3Ease of manufacture
If membrane-based assay devices are used to simplify the system, then ease of manufacture and portability improve, but analyte concentration is diluted by fluid flow, reducing detection accuracy
Solution Approach 1:
The patent changes the fluid flow dimension from lateral (horizontal) flow through a membrane to vertical flow through a microfluidic channel with curved bottom. This dimensional change utilizes centrifugal force to concentrate analytes vertically at the detection zone, preventing dilution while maintaining the simplicity of membrane-based assay devices
Solution Approach 2:
The patent modifies the flow dynamics parameter by creating a curved channel geometry that generates centrifugal force. This parameter change in flow pattern transforms the dilution effect into a concentration effect, where the curved path causes analytes to band vertically rather than disperse horizontally, improving detection accuracy
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
The system is portable, inexpensive, and provides improved sensitivity and accuracy by minimizing the distance between the illumination source and detector, reducing the need for complex components, and enhancing the signal-to-noise ratio.
Implementation Method 1
an illumination source capable of providing electromagnetic radiation that causes the detection probes to produce the detection signal
Implementation Method 2
The chromatographic medium is transmissive to the electromagnetic radiation and the detection signal
Data Source
AI summary
A system that employs transmission-based detection techniques to determine the presence or concentration of an analyte within a test sample is provided. Specifically, the optical detection system contains a chromatographic-based assay device that is positioned in the electromagnetic radiation path defined between an illumination source and detector. To enhance the sensitivity and signal-to-noise ratio of the system without significantly increasing costs, the distance between the illumination source and/or detector and the assay device is minimized. The illumination source and/or detector may also be positioned directly adjacent to the assay device. In addition, the system may be selectively controlled to reduce reliance on external optical components, such as optical filters or diffusers.