Microfluidic Device Sequential Metering Capillary Overflow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microfluidic devices are limited in their ability to sequentially and accurately meter multiple volumes of fluid, often leading to contamination and inaccuracy due to inadequate fluid isolation and reliance on mechanical means for metering.
Innovation Solution
A microfluidic device with a sample input chamber, first and second overspill chambers, and a metering conduit that uses capillary action to meter fluid volumes, with absorbent pads to absorb excess fluid and a fluid-actuated closable valve to isolate the second metered volume, enabling sequential and accurate metering of fluid volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If capillary action is used to passively meter fluid volumes, then mechanical complexity is reduced, but the ability to sequentially meter multiple precise volumes deteriorates
Solution Approach 1:
The device is divided into multiple independent metering stages, each with its own metering channel and overflow chamber. The first metering channel meters a first volume from the input fluid, and the second metering channel meters a second volume from the first metered fluid. This segmentation allows each channel to be optimized for precise passive metering while enabling sequential operation to achieve multiple precise volume measurements without mechanical complexity.
2Measurement precision
If excess fluid is allowed to flow through overflow channels, then metering accuracy is improved, but fluid contamination worsens
Solution Approach 1:
The harmful excess fluid is extracted and isolated from the main fluid path by directing it into separate overflow chambers (first overflow chamber and second overflow chamber). These chambers are positioned and configured so that excess fluid flows away from the metered volumes and does not contaminate the device housing or interfere with subsequent operations. This extraction of the harmful element (excess fluid) resolves the contradiction by maintaining metering accuracy while preventing contamination.
3Object-affected harmful factors
If absorbent material is used to contain excess fluid, then contamination is prevented, but the ability to maintain liquid form deteriorates
Solution Approach 1:
The device applies different treatments to different portions of the fluid system. The metering channels and reaction chambers maintain fluid in liquid form for operational flexibility, while the overflow chambers use absorbent material to contain excess fluid and prevent contamination. This local differentiation of fluid state (liquid in operational zones, absorbed in containment zones) resolves the contradiction by preventing contamination where needed while maintaining liquid form where operational flexibility is required.
4Adaptability or versatility
If a fluid-actuated closable valve is introduced to isolate metered fluid, then operational versatility is improved, but device complexity worsens
Solution Approach 1:
The fluid-actuated closable valve is designed to open and close automatically in response to fluid flow and pressure changes during the metering process. The valve opens to allow fluid passage during metering and closes automatically to isolate the metered fluid volume for subsequent operations. This self-acting mechanism provides operational versatility (ability to perform multiple operations on isolated fluid) without requiring external mechanical control systems, thereby limiting the increase in device complexity.
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 device effectively handles varying input volumes, prevents contamination by absorbing excess fluid, and allows for multiple fluidic operations on the second metered volume, reducing reagent usage and enhancing operational ease.
Implementation Method 1
a metering conduit (14) in fluid communication with the sample fluid input chamber and the first overspill chamber, wherein the metering conduit meters a first metered volume of fluid from the sample fluid
Implementation Method 2
the first overspill chamber includes a first absorbent pad for absorbing the fluid in excess of the first metered volume of fluid
Implementation Method 3
the second overspill chamber has a fluid actuated closable valve for controlling the metering of the second metered volume of fluid
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An integrated fluidic device includes an input chamber (4) that provides an input of a sample fluid, and a first overspill chamber (6) in fluid communication with the input chamber. A metering conduit (14) is in fluid communication with the fluid input chamber and the first overspill chamber. The metering conduit meters a first metered volume of fluid from the sample fluid, and the first overspill chamber receives fluid in excess of the first metered volume of fluid. A second overspill chamber (20) is in fluid communication with the metering conduit. The metering conduit meters a second metered volume of fluid from the first metered volume of fluid, and the second overspill chamber receives fluid from the first metered volume of fluid in excess of the second metered volume of fluid. The second overspill chamber has a fluid actuated closable valve (24) for controlling the metering of the second metered volume of fluid.