Microfluidic Sample Metering and High-Ratio Capillary Dilution
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Solution Overview
Problem
Existing microfluidic systems face challenges in precisely metering and diluting liquid samples, particularly in capillary-driven systems, as they struggle to control fluid flow and achieve high dilution ratios, leading to inefficiencies in processing large samples.
Innovation Solution
A microfluidic system with a sample inlet, channels, and valves configured for capillary action, allowing precise metering and dilution by using capillary trigger valves and pumps to control fluid flow, enabling a high dilution ratio in a single step with reduced complexity and flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capillary action is used to draw sample liquid in existing microfluidic systems, then the system can process liquid samples, but the system cannot precisely meter the sample volume because the fluid stream cannot be shut off or closed off once it has started
Solution Approach 1:
The system divides the sample liquid path into multiple segments with separate valves (first valve, second valve, third valve) that can be independently controlled. This allows the sample liquid to be drawn in controlled increments and shut off at specific points, enabling precise volume metering while maintaining ease of operation through independent valve control of each segment.
2Productivity
If a relatively large blood sample is added to the system, then sufficient sample is available for analysis, but the entire sample cannot be processed since only a minute quantity is needed and precise volume control is required
Solution Approach 1:
The system extracts only the required minute quantity of sample liquid from the larger sample volume using controlled capillary action and valve management. The sample liquid is drawn through controlled paths and shut off at specific points, allowing efficient processing of only the necessary amount while leaving the majority of the sample unprocessed, thus resolving the contradiction between processing efficiency and volume control precision.
3Adaptability or versatility
If capillary driven systems are used for sample processing, then the system can analyze biological samples, but high dilution ratios cannot be reached and sufficient dilution with buffer is difficult
Solution Approach 1:
The system merges the sample liquid path with the buffer liquid path through a common channel section after the valves. By combining these paths, the system achieves high dilution ratios in a single step without requiring complex separate dilution mechanisms, thus improving adaptability while reducing overall system complexity.
4Measurement precision
If multiple valves and components are used to achieve precise metering and dilution, then the system can control fluid flow accurately, but the number of components increases
Solution Approach 1:
The valves in the system are designed to serve multiple functions: they control sample liquid flow, enable volume metering, and facilitate dilution processes. This multi-functionality allows the system to achieve precise fluid flow control without requiring separate dedicated components for each function, thus reducing the overall number of components while maintaining measurement precision.
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 achieves precise metering of sample volumes, allows high dilution ratios, reduces the number of components, and minimizes flow resistance, resulting in efficient and rapid sample processing.
Implementation Method 1
a first sample channel connecting the sample inlet and a first valve and being configured to draw sample liquid, by capillary action, from the sample inlet to the first valve
Data Source
AI summary
The present disclosure relates to a microfluidic system and a method for diluting a sample liquid having a predetermined volume. The present disclosure further relates to a diagnostic device comprising the microfluidic system. An example system comprises: a sample inlet; a first sample channel connecting the sample inlet and a first valve; a second sample channel connecting the first valve and a capillary pump; a sample metering channel having a first end connected to a second valve and a second end connected to a third valve, wherein the first valve is connected to the sample metering channel between the first end and the second end. The system further comprises: a buffer inlet; a first buffer channel connecting the buffer inlet and the second valve; an outlet channel connected to the third valve; and a second buffer channel connecting the second valve and the third valve.