Microfluidic Chip Rectangular Waveguides Evanescent Fluorescence Detection
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Solution Overview
Problem
Current point-of-care diagnostics devices lack the sensitivity and accuracy to replace clinical laboratory tests, and existing fluorescence detection systems are limited by the need for large optical readers and complex fluidic control, making them unsuitable for portable and cost-effective applications.
Innovation Solution
A microfluidic chip with integrated rectangular waveguide structures that use evanescent wave excitation to efficiently guide excitation light and enhance fluorescence detection, allowing for high-sensitivity assays with improved signal-to-noise ratio and reduced complexity, while being producible at low costs and disposable after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluorescence detection systems are used, then detection sensitivity can be achieved, but the device size and complexity increase due to large optical readers and complex fluidic control
Solution Approach 1:
The patent combines the optical waveguide structures directly with the microfluidic channel substrate, integrating the excitation light guidance function into the assay chip itself. This eliminates the need for separate large optical readers and complex fluidic control systems, achieving high-sensitivity fluorescence detection in a compact, simple device suitable for point-of-care use.
Solution Approach 2:
The patent replaces complex mechanical fluidic control systems with passive microfluidic channels that rely on capillary action and diffusion for sample transport. This substitution eliminates the need for pumps, valves, and complex control mechanisms while maintaining efficient sample delivery to the detection zones.
2Measurement precision
If conventional fluorescence detection systems are used, then detection sensitivity can be achieved, but manufacturing costs increase
Solution Approach 1:
By integrating the waveguide structures directly into the microfluidic chip substrate using standard microfabrication techniques, the patent eliminates the need for separate expensive optical components and assembly processes. This integration significantly reduces manufacturing costs while maintaining high detection sensitivity.
Solution Approach 2:
The patent uses standard semiconductor manufacturing parameters and materials that can be produced using existing industrial infrastructure, enabling cost-effective mass production of high-sensitivity fluorescence detection chips for point-of-care applications.
3Use of energy by moving object
If evanescent wave excitation is used, then excitation power efficiency is improved, but the uniformity of excitation field across multiple assay areas becomes challenging
Solution Approach 1:
The patent divides the chip into multiple independent assay areas, each with its own waveguide structure and evanescent field excitation zone. This segmentation allows each assay area to be optimized independently for uniform excitation while maintaining overall system efficiency, enabling multiplexed detection without cross-interference.
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 solution enables high-sensitivity and precise fluorescence-detected assays with efficient use of excitation power, providing a uniform evanescent wave excitation field across multiple assay areas, distinguishable fluorescence signals, and simplified optical detection, suitable for point-of-care diagnostics without the need for pre-treated physiological samples.
Implementation Method 1
rectangular waveguide structures arranged on the chip that are able to guide excitation light... such that an evanescent field of light guided within the waveguide structure overlaps with a certain part of the inner volume of the microfluidic channel
Implementation Method 2
one or more lateral surfaces of the core of the waveguide structure at least partially face the inner volume of the microfluidic channel, such that an evanescent field of light guided within the waveguide structure overlaps with a certain part of the inner volume of the microfluidic channel
Implementation Method 3
Fluorescence is one of the main transduction techniques used for biochemical detection... A fluorescent molecule (fluorophore), being in a ground energy state, absorbs a photon at a certain excitation wavelength. After internal relaxation of the excited state to a lower energy level, a photon is spontaneously emitted, resulting in fluorescence radiation.
Data Source
AI summary
An assay unit for carrying-out fluorescence-detected assays having a microfluidic chip with a microfluidic system to convey a sample or analyte solution through one or more microfluidic channels arranged on the chip, and a photonic system with two or more rectangular waveguide structures. The microfluidic channels and the waveguide structures cross each other at a detection site. In an assay area, where a certain microfluidic channel and a certain waveguide structure cross each other, one or more lateral surfaces of the core of the waveguide structure at least partially face an inner volume of the microfluidic channel, such that an evanescent field of light guided within the waveguide structure overlaps with a certain part of the inner volume of the microfluidic channel.