Microfluidic Pillar Angles for Passive Priming
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Solution Overview
Problem
Microfluidic devices often face challenges during passive priming, where fluid flow is incomplete due to insufficient capillary forces, leading to pinning and gas pocket trapping, especially in life sciences applications where surfactants cannot be used without contaminating the sample.
Innovation Solution
The design of microfluidic devices with strategically oriented and angled pillars within the chamber, where the sum of the turn and pillar angles is less than a threshold angle based on the fluidic contact angle, promotes fluid flow without surfactants and standard material changes, ensuring complete chamber filling without gas trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surfactants are added to promote fluid flow during passive priming, then fluid flow is improved, but sample contamination occurs in life sciences applications
Solution Approach 1:
The patent removes surfactants from the fluid system and instead extracts the flow-promoting function into the chamber geometry itself through strategically positioned pillars with specific angle relationships, eliminating the source of contamination while maintaining fluid flow capability
Solution Approach 2:
The chamber structure itself provides the flow-promoting function through its geometric design, with pillars arranged to create capillary forces that drive fluid flow without requiring external additives like surfactants, making the system self-sufficient
2Productivity
If capillary forces are increased to improve passive priming, then fluid flow is improved, but gas pockets become trapped in the chamber
Solution Approach 1:
The chamber is segmented into multiple regions by strategically placing pillars that divide the flow path, creating controlled capillary channels that guide fluid flow while preventing gas pocket accumulation in any single location
Solution Approach 2:
The pillars are positioned with specific local geometric characteristics (turn angles and pillar angles) that create localized capillary effects to promote flow in specific directions while avoiding gas trapping in particular regions
3Stability of the object's composition
If chamber pillars are added to prevent collapse, then structural stability is improved, but fluid flow during priming becomes incomplete
Solution Approach 1:
The chamber pillars serve dual functions: providing structural support to prevent chamber collapse and simultaneously acting as flow-promoting elements through their specific geometric arrangement and angle relationships, eliminating the trade-off between stability and flow
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 enables complete fluid flow during passive priming without surfactants, maintaining the integrity of biological samples and using standard manufacturing processes, thus being suitable for life sciences applications without increasing fabrication costs.
Implementation Method 1
passive priming in which no external forces like pumps are used, and instead capillary and other forces resulting from the interaction of the fluid and the material from which the microfluidic device is fabricated cause the flow of fluid
Data Source
AI summary
A microfluidic device includes a chamber having a floor, a ceiling, and an inlet. The microfluidic device includes pillars extending from the floor to the ceiling of the chamber. Each pillar has a leading surface or corner, a trailing surface or corner opposite the leading surface or corner, and trailing side surfaces adjoining the trailing surface or corner. Each pillar is oriented along a corresponding ray intersecting the leading surface or corner and the trailing surface or corner. Adjacent pillars have a turn angle between the corresponding rays of the adjacent pillars, and each pillar has a pillar angle between the trailing side surfaces thereof. The turn and pillar angles are based on a fluidic contact angle to promote fluid flow from the inlet throughout the chamber during priming without fluidic pinning.