Open Microfluidic Channels for Reliable Fluid Handling
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Solution Overview
Problem
Existing open microfluidic channels face challenges in controlling fluid flow, inserting or removing fluid, and creating advanced fluid handling platforms due to limitations in understanding flow dynamics and lack of tools for precise fluid manipulation.
Innovation Solution
The development of shallow open microchannels that allow for spontaneous capillary flow by optimizing the ratio of free interface to wetted surface area, enabling complex network designs for precise fluid handling and integration with diagnostic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional closed channel setups are used, then air bubbles are trapped inside the channels, but manufacturing complexity increases due to bonding requirements
Solution Approach 1:
The patent removes the top wall of the microchannel to create an open microchannel configuration. This extraction of the enclosing structure eliminates the need for bonding operations while allowing air bubbles to escape, thereby improving device reliability without increasing manufacturing complexity. The open channel design is fabricated using a single molding step, contrasting with closed channels that require multiple bonding steps.
Solution Approach 2:
The microchannel is segmented into an open configuration where the top wall is separated from the bottom and side walls. This segmentation creates an open interface that allows air bubbles to escape while maintaining fluid flow control through the remaining structured walls. The segmented design simplifies fabrication by eliminating the need to bond the top wall to the base structure.
2Reliability
If open microfluidic channels are used, then air bubbles can escape improving reliability, but flow control capability is limited
Solution Approach 1:
The patent applies local quality by creating heterogeneous surface properties within the open microchannel. Hydrophilic regions are introduced at specific locations to control fluid flow direction and rate, while hydrophobic regions prevent unwanted fluid spreading. This local differentiation of surface properties enables precise flow control in the open channel configuration, overcoming the limitation of poor flow control while maintaining the reliability benefits of air bubble escape.
Solution Approach 2:
The microchannel design incorporates dynamic flow control mechanisms where fluid flow characteristics can be adjusted by modifying surface properties or channel geometry at different locations. The open channel allows dynamic adjustment of flow rates and directions through controlled wettability patterns, enabling versatile fluid handling despite the open configuration.
3Adaptability or versatility
If complex microfluidic networks are designed, then advanced fluid handling is enabled, but manufacturing cost and complexity increase
Solution Approach 1:
The complex microfluidic network is divided into modular open channel segments that can be independently fabricated using single-step molding techniques. Each segment maintains open channel characteristics for simplified manufacturing, and the modules can be assembled to create complex fluid handling networks. This segmentation enables advanced functionality without proportionally increasing manufacturing complexity or cost.
Solution Approach 2:
The patent uses master molds to create precise replicas of complex microchannel networks through molding processes. The master mold defines the three-dimensional geometry of the open channels, and multiple copies can be produced simultaneously or sequentially at low cost. This copying approach enables complex fluid handling networks to be manufactured economically without requiring complex fabrication processes for each individual device.
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 allows for reliable, scalable, and cost-effective manufacturing of complex microfluidic networks, enabling advanced fluid handling and diagnostic applications with improved reliability and functionality.
Implementation Method 1
spontaneous capillary flow by optimizing the ratio of free interface to wetted surface area
Data Source
AI summary
Various collection devices, systems and methods relating to the use of devices with open microfluidic channels disposed within a housing defining a lumen. These devices make use of microneedles passed through apertures to induce fluid flow into microfluidic channel networks for collection and analysis. The device can be actuated via button when placed on the skin of a patient to collect a fluid sample, such as a blood draw.