Microfluidic Probe Head with Bypass for Liquid Volume Separation
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Solution Overview
Problem
Microfluidic probe heads struggle to deliver a sequence of separate liquid volumes without mixing due to advective and diffusive effects, especially in wet environments, where hydrodynamic flow confinement is desired, and existing solutions are not applicable for local chemistry, leading to spreading and contamination of the target surface.
Innovation Solution
A microfluidic probe head with an inlet, outlet, first fluid channel, second fluid channel, and a fluid bypass that allows spacers to be removed from the first fluid channel, enabling the delivery of a free sequence of separate liquid volumes to a deposition area while preventing spacers from reaching the surface, utilizing hydrodynamic flow confinement to maintain laminar flow and prevent mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spacers of immiscible-phase fluid are inserted between sequential plugs to prevent mixing, then the concentration gradient between plugs is maintained, but the spacers come into direct contact with the target surface causing contamination and spreading
Solution Approach 1:
The harmful spacers are extracted from the delivery path before reaching the target surface. The device removes spacers from the first fluid channel through a fluid bypass, allowing only the liquid plugs to contact the deposition area, thereby eliminating surface contamination while preserving concentration gradients
Solution Approach 2:
A fluid bypass acts as an intermediary pathway that redirects spacers away from the target surface. This mediator channel allows spacers to be removed from the main delivery channel without interfering with the sequential delivery of liquid plugs to the deposition area
2Productivity
If sequential liquid volumes are delivered to a target surface, then multiple chemical steps can be performed, but advective and diffusive effects cause mixing between volumes
Solution Approach 1:
The device maintains continuous laminar flow throughout the sequential delivery process, ensuring that liquid volumes are delivered without interruption while preventing mixing through sustained hydrodynamic confinement. The flow regime is maintained from generation through delivery to deposition
Solution Approach 2:
The device exploits changes in flow parameters, specifically maintaining low Reynolds number laminar flow conditions that suppress turbulent mixing. By controlling flow rates and channel dimensions, the system achieves deterministic transport where diffusion is minimized and advective effects dominate, preserving volume separation
3Manufacturing precision
If hydrodynamic flow confinement is used to prevent mixing in wet environments, then laminar flow is maintained, but existing solutions are not applicable for local chemistry deposition
Solution Approach 1:
The device combines multiple functions into a single integrated system: it generates sequential liquid volumes, maintains hydrodynamic flow confinement, removes spacers, and enables localized deposition. This multi-functional design allows the same device to perform both flow control and precise spatial deposition in wet environments
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 solution effectively prevents mixing of sequential liquid volumes, maintains the integrity of solute and particle concentration, and allows for localized deposition without contaminating the target surface, enhancing the precision and efficiency of microfluidic processes in wet environments.
Implementation Method 1
utilizing hydrodynamic flow confinement to maintain laminar flow and prevent mixing
Implementation Method 2
utilizing hydrodynamic flow confinement to maintain laminar flow and prevent mixing
Implementation Method 3
The immiscible-phase spacers prohibit a diffusion of solutes and/or particles between sequential plugs
Data Source
AI summary
Microfluidic probe head for processing a sequence of separate liquid volumes separated by spacers. The microfluidic probe head includes: an inlet, an outlet, a first fluid channel and a second fluid channel and a fluid bypass connecting the first fluid channel and the second fluid channel. The first fluid channel delivers the sequence of separate liquid volumes from the inlet toward a deposition area, the fluid bypass allows the spacers to be removed from the first fluid channel obtaining a free sequence of separate liquid volumes without spacers, the first fluid channel delivers the free sequence of separate liquid volumes to the deposition area, and the second fluid channel delivers the removed spacers from the fluid bypass to the outlet. The present invention also provides a microfluidic probe and method for processing a sequence of separate liquid volumes.