Assay Chip with Evanescent Wave Detection for Microfluidic Binding
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Solution Overview
Problem
Conventional biochemical assays face challenges in efficiently performing first reaction processing, particularly in binding analytes with fluorescent labels in Micro Total Analysis Systems, leading to lower detection accuracy due to difficulties in stirring solutions and ensuring proper binding.
Innovation Solution
An assay chip with a pot for pre-processing and first reaction processing, featuring a fluidic channel with a detection region for light output from photoresponsive labeling substances, including a dielectric plate and metal coating for evanescent wave excitation, and dry reagents fixed to the inner surface to prevent detachment, allowing for efficient binding and measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Micro Total_analysis Systems are used to reduce sample amount and increase detection speed, then productivity is improved, but the analyte and fluorescent label cannot sufficiently bind due to difficulty in stirring the solution, leading to lower measurement precision
Solution Approach 1:
The device is divided into distinct functional modules: a reaction chamber for binding reactions and a detection chamber for fluorescence measurement. This segmentation allows optimized conditions for each function - sufficient reaction time in the reaction chamber while maintaining fast detection in the detection chamber, resolving the contradiction between productivity and measurement precision
Solution Approach 2:
A fluid delivery system acts as an intermediary between sample introduction and detection, enabling controlled transport of the analyte-label complex. This intermediary system ensures complete binding occurs during transport while maintaining the microfluidic advantages of small sample volume and fast detection
2Ease of operation
If conventional fluorescence detection apparatus is used, then detection capability is provided, but separate first reaction processing and second reaction processing are required, increasing device complexity
Solution Approach 1:
The reaction chamber and detection chamber are merged into a single integrated device structure. The binding reaction and fluorescence detection occur in sequence within the same device, eliminating the need for separate processing equipment and simplifying operation while maintaining detection capability
Solution Approach 2:
The device performs multiple functions within a single system: it conducts the binding reaction between analyte and fluorescent label, transports the complex, and detects the fluorescence signal. This multi-functionality reduces device complexity while preserving ease of operation
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 assay chip enables high-sensitivity measurement by ensuring effective binding of analytes and labels, improving detection accuracy and simplifying the measurement process through linear arrangement of components and automatic processing capabilities.
Implementation Method 1
The detection region includes a dielectric plate for making excitation light for generating evanescent waves enter, and a metal coating applied to a predetermined region on a sample-solution-contact surface of the dielectric plate
Data Source
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AI summary
An assay chip efficiently carries out first-reaction through second-reaction processing. An assay chip (10) includes fluidic-channel member (11, 12) composed of a light-transmissive lower member (11) and an upper member (12), forming a fluidic-channel (15) therebetween, and a cover member (13) fitted with the fluidic-channel member (11, 12) from the upper-member-(12)-side thereof. An inlet (12a) for injecting a sample solution into the fluidic-channel (15) and a suction opening (12b) for sucking, from the downstream side, the injected sample solution, both communicating with the fluidic-channel (15), are formed on the upper surface of the upper member (12). A pot (13a) for carrying out predetermined pre-processing on the sample solution, a pot (13b) for first-reaction processing to bind a photoresponsive labeling substance to an analyte in the sample solution, an inlet insertion-hole (13c) for inserting the inlet (12a), and a suction-opening insertion-hole (13d) for inserting the suction opening (12b) are linearly arranged on the upper surface of the cover member (13).