Oil-Free Microfluidic Serial Dilution Platform
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Solution Overview
Problem
Current microfluidic devices for serial dilution require precise fluidic control, external manifolds, and an immiscible oil phase for droplet trapping and dilution, which can lead to contamination and non-uniform particle trapping, and necessitate additional equipment and complex control systems.
Innovation Solution
A microfluidic serial dilution platform using an oil-free immiscible phase driven by manual or electronic pipettors, featuring hydrophilic or hydrophobic capillary constriction channels and bypass channels, allowing for passive droplet trapping and serial dilution without external forces or oil contamination, enabling uniform particle trapping and integration with conventional pipetting systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an immiscible oil phase is used to prevent droplet escape from traps, then droplet trapping reliability is improved, but oil contamination occurs and additional external controls are required
Solution Approach 1:
The patent removes the immiscible oil phase from the system entirely, replacing it with a hydrophobic coating on the capillary constriction channels. This extraction of the harmful substance (oil) while maintaining the trapping function through surface chemistry modification resolves the contradiction between reliable trapping and contamination prevention
Solution Approach 2:
The invention changes the surface property parameter of the capillary channels by applying a hydrophobic coating, transforming them from hydrophilic to hydrophobic. This parameter change enables the channels to repel aqueous droplets and prevent escape without requiring oil, thus maintaining reliability while eliminating contamination
2Productivity
If coalescence between diluting stream and trapped droplets is used for serial dilution, then dilution is achieved, but composition of the diluting plug is altered causing adverse reactions
Solution Approach 1:
The patent segments the dilution process into discrete steps where diluted droplets are formed and immediately separated into individual traps. Each trap becomes an isolated compartment containing a specific dilution, preventing interaction between different dilution stages and maintaining composition stability throughout the serial dilution process
Solution Approach 2:
The hydrophobic capillary constriction channels act as an intermediary mechanism that enables controlled droplet ejection and trapping. This intermediary structure allows dilution to occur through controlled mixing at the trap entrance while preventing unwanted coalescence downstream, thus maintaining diluting plug composition stability
3Device complexity
If passive fragmentation method is used for droplet trapping, then external controls are reduced, but uniform particle trapping is poor
Solution Approach 1:
The patent applies local quality modification by coating only the capillary constriction channels with hydrophobic material, while leaving other parts of the device with different properties. This localized hydrophobic treatment creates specific zones for controlled droplet ejection and uniform particle trapping without requiring complex external controls throughout the entire system
4Reliability
If pre-filled traps with immiscible oil phase are used, then droplet escape is prevented, but additional equipment and complex control systems are required
Solution Approach 1:
The hydrophobic capillary constriction channels provide self-service functionality by automatically preventing droplet escape through their inherent surface properties. The channels self-regulate droplet containment based on surface tension and hydrophobic effects, eliminating the need for external manifolds, pumps, or complex control systems to maintain droplet containment
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 solution eliminates oil-related contamination, reduces equipment needs, and achieves efficient, uniform droplet trapping and dilution, comparable or superior to high-throughput robotic systems, with reduced costs and enhanced throughput, while preventing composition changes during dilution.
Implementation Method 1
hydrophobic capillary constriction channels
Implementation Method 2
capillary plug in the constriction that immediately follows the trap to ensure that the droplets do not escape
Implementation Method 3
hydrophilic capillary constriction channels
Data Source
AI summary
Described is a microfluidic serial dilution platform based well-plate using an oil-free immiscible phase driven by manual or electronic pipettors. The well-plate includes a plurality of fluidic traps, a plurality of hydrophilic capillary constriction channels and a plurality of bypass channels. Each of the plurality of bypass channels is associated with one of the plurality of fluidic traps, each of the plurality of hydrophilic capillary constriction channels is associated with one of the plurality of fluidic traps, and each of the plurality of fluidic traps is associated with one of the plurality of bypass channels and one of the plurality of hydrophilic capillary constriction channels. The well-plate further includes an inlet, an outlet, and a main channel with a plurality of portions that connects the inlet to the plurality of fluidic traps, associated hydrophilic capillary constriction channels and associated bypass channels, and the outlet.