Microfluidic System for Precise Sample Volume Metering
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Solution Overview
Problem
Existing microfluidic systems face challenges in precisely metering a predetermined volume of fluid using capillary action, as they cannot effectively stop fluid streams once they start, leading to inaccurate sample processing in applications like blood cell analysis.
Innovation Solution
A microfluidic system with a sample reservoir and buffer reservoir connected through capillary channels and valves, allowing buffer fluid to replace sample fluid in specific channels, isolating a predetermined volume of sample fluid without actively controlling flows, using capillary action and flow resistances to control the flow rates and mixing ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capillary action is used to transport fluid through microchannels, then passive fluid control is achieved, but the ability to stop or close off fluid streams is lost
Solution Approach 1:
A buffer fluid is introduced as an intermediary substance that displaces the sample fluid through the microchannel. The buffer fluid acts as a mediator to push the sample fluid forward and isolate it in a specific channel segment, enabling volume control without active pumping mechanisms.
Solution Approach 2:
The microfluidic system is divided into multiple discrete channel segments (first microchannel, second microchannel, third microchannel) with defined volumes. By isolating the sample fluid in a specific segment and using buffer fluid to replace excess sample, precise volume metering is achieved through spatial segmentation rather than active flow control.
2Quantity of substance
If a relatively large blood sample is added to ensure sufficient volume, then sample availability is improved, but processing accuracy deteriorates due to inability to precisely meter the volume
Solution Approach 1:
The system extracts only the required portion of the sample fluid by allowing buffer fluid to displace and replace the excess sample fluid in the microchannels. The sample fluid is drawn into the microchannels by capillary action, then buffer fluid is introduced to push back and isolate a precise volume, effectively taking out only the needed amount from the larger sample.
Solution Approach 2:
Buffer fluid serves as an intermediary that enables precise volume measurement by displacing the sample fluid. The buffer fluid is introduced through a separate reservoir and channel system, allowing it to push the sample fluid to a specific position and isolate a predetermined volume without requiring active pumping or complex control mechanisms.
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
Enables precise metering and isolation of a predetermined volume of sample fluid, enhancing analysis by ensuring accurate sample volume and reducing the need for large initial sample volumes, while allowing for precise control of fluid mixing ratios.
Implementation Method 1
the first sample channel is arranged to draw sample fluid from the sample reservoir to fill the first, second, third, fourth, and fifth sample channels by capillary action
Implementation Method 2
the first trigger channel is arranged to draw buffer fluid from the buffer reservoir, by capillary action, to the exit channel
Data Source
Figure 1A~1B
Figure 2A~2E
Figure 3
AI summary
The present invention relates to a microfluidic system (10, 20) comprising: a sample reservoir (110, 210); a first sample channel (120, 220) connected to the sample reservoir (110, 210), branching off into a second sample channel (122, 222) ending in a first valve (130, 230), and into a third sample channel (124, 224) which branches off into a fourth sample channel (126, 226) ending in a second valve (132, 232), and into a fifth sample channel (128, 228) ending in a third valve (134, 234); a buffer reservoir (140, 240); a first trigger channel (150, 250) arranged to connect the buffer reservoir (140, 240) to the second valve (132, 232); a second trigger channel (152, 252) connecting the second valve (132, 232) and the first valve (130, 230); and an exit channel (154, 254) connected to the first valve (130, 230).