Microfluidic Filling via Light Signal Detection
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Solution Overview
Problem
Conventional automatic dispensing systems for point-of-care in-vitro diagnostics face challenges such as dead volumes, reagent mixing, air presence in fluidic paths, and high costs, which affect the accuracy and reproducibility of reagent dispensing, leading to long hands-on time and potential false results.
Innovation Solution
A method involving a dispensing system with at least two containers connected via micropumps and nozzles, utilizing photosensitive sensors with photodetectors to ensure complete filling of the fluidic path, prevent reagent mixing, and maintain aseptic conditions by detecting light signals from chemical reactions to confirm reagent presence and correct volume dispensing, eliminating the need for rinsing and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional automatic dispensing systems use separate fluidic paths and rinsing solutions to prevent reagent mixing, then reagent contamination is prevented, but device complexity and system cost increase
Solution Approach 1:
The patent merges the filling function and rinsing function into a single fluidic path. The same nozzle and fluidic channel are used to dispense both the reagent solution and the rinsing solution sequentially, eliminating the need for separate fluidic paths. This is achieved by controlling the micropump to first fill the nozzle with reagent, then rinse it with cleaning solution, and finally dry it, all through the same fluidic components.
Solution Approach 2:
The patent performs preliminary rinsing and drying actions between reagent dispensing operations. Before the next reagent is dispensed, the nozzle is automatically rinsed with cleaning solution and then dried by continuing to pump until air bubbles are detected. This preliminary action prevents contamination of the next reagent and eliminates the need for complex separate rinsing systems.
2Device complexity
If manual dripping is used to add reagents, then system complexity is reduced, but hands-on time increases and reproducibility decreases
Solution Approach 1:
The system performs self-service by automatically detecting when the nozzle is full and when rinsing is complete. The control unit monitors the pumping process and automatically determines when to stop filling based on pressure sensors detecting the meniscus position, and when to stop rinsing based on air bubble detection. This automation eliminates the need for manual intervention while keeping the system relatively simple.
3Manufacturing precision
If separate containers and rinsing solutions are used to fill nozzles, then complete filling is achieved, but loss of substance increases
Solution Approach 1:
The patent extracts the rinsing function from a separate process and integrates it into the main dispensing sequence. By taking out the rinsing step and performing it immediately after filling through the same nozzle, the system ensures complete filling accuracy while minimizing reagent waste. The rinsing solution is drawn from the same container through the same fluidic path, eliminating the need for additional rinsing containers and reducing overall substance loss.
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 ensures accurate, reproducible, and cost-effective dispensing of reagents, reducing hands-on time, preventing false results, and maintaining aseptic conditions, while eliminating the need for additional rinsing solutions and sensors, resulting in a compact and efficient point-of-care system.
Implementation Method 1
measuring a light signal, in particular chemiluminescence signal, by reacting the first solution, in particular chemiluminescence solution and the further solution, in particular enzyme solution, in the measuring area of the microfluidic device
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a method for filling a microfluidic device (3) using a dispensing system (2), said method comprising at least the following steps: (a) transporting the solution from the container (6) to the sample application opening (13) of the microfluidic device (3) via the nozzle (11) of the dispensing system (2) using a micropump (10); (b) further transporting the solution into the measuring region of the microfluidic channel (14) of the microfluidic device (3); (c) measuring a light signal in the measuring region of the microfluidic device (3) using at least one photosensitive sensor (4) with a plurality of photodetectors (5); and (d) deactivating the micropump (10) if the light signal is detected and/or if the light signal changes.