EWOD Droplet Interface Bilayers for In-Device Concentration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing EWOD devices face challenges in efficiently concentrating or diluting fluid droplets within the device due to their enclosed nature, making conventional methods ineffective, and the separation of components from reaction droplets difficult.
Innovation Solution
A method involving the formation of a droplet interface bilayer (DIB) between two droplets with differing osmotic pressures, allowing solvent transfer through the bilayer to concentrate or dilute the fluid in one droplet while maintaining the integrity of the other, facilitated by electro-wetting electrode actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional concentration or dilution methods are used in enclosed EWOD devices, then device simplicity is maintained, but efficient concentration or dilution of droplets cannot be achieved
Solution Approach 1:
The invention changes the physical-chemical parameters of the droplet interface by forming a droplet interface bilayer (DIB) between two droplets with different osmotic pressures. This parameter change enables solvent transfer through osmosis across the DIB, achieving efficient concentration or dilution without requiring external equipment, thus resolving the contradiction between device simplicity and operational efficiency
Solution Approach 2:
The droplet interface bilayer (DIB) acts as an intermediary structure between two droplets, enabling selective solvent transfer while maintaining droplet separation. This intermediary mechanism allows efficient concentration or dilution operations within the enclosed EWOD device without compromising device simplicity or requiring complex external systems
2Stability of the object's composition
If droplets are separated to maintain integrity, then droplet purity is maintained, but solvent transfer between droplets is prevented
Solution Approach 1:
The droplet interface bilayer (DIB) serves as a controlled intermediary that enables selective solvent transfer between droplets while maintaining their physical separation and integrity. The DIB acts as a semipermeable membrane that allows water molecules to pass through via osmosis while preventing complete mixing of droplet contents, thus resolving the contradiction between maintaining droplet integrity and enabling solvent transfer
Solution Approach 2:
The invention creates a localized region of different properties at the droplet interface by forming the DIB. This local quality change at the interface allows selective permeability - enabling solvent transfer where needed while maintaining droplet integrity elsewhere, thus resolving the contradiction between droplet stability and solvent transfer capability
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
Enables efficient concentration or dilution of droplets within EWOD devices, allowing for better control over droplet size and composition, facilitating further reactions or removal processes.
Implementation Method 1
maintain the first and second droplets contacting each other to maintain the droplet interface bilayer and thereby allow a solvent species to pass from the first droplet to the second droplet via the droplet interface bilayer
Implementation Method 2
the second droplet containing fluid of a second composition different to the first composition and containing a higher osmolarity solute, than the first composition and so having a higher osmotic pressure
Implementation Method 3
selectively actuating the electro-wetting electrodes to: cause first and second droplets in a fluid medium in the fluid chamber of the EWOD device to contact each other to form a droplet interface bilayer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The disclosure relates to a method of manipulating droplets in an electro-wetting on dielectric (EWOD) device, the EWOD device having first and second substrates defining a fluid chamber therebetween and a plurality of electro-wetting electrodes. The method comprises selectively actuating the electro-wetting electrodes to: cause first and second droplets in a fluid medium in the fluid chamber of the EWOD device to contact each other to form a droplet interface bilayer, the first droplet containing fluid of a first composition including a first solvent species and the second droplet containing fluid of a second composition, the second composition being different to the first composition and containing a solute at a higher osmolarity than the first composition and so having a higher osmotic pressure; maintain the first and second droplets contacting each other to maintain the droplet interface bilayer and thereby allow a solvent species to pass from the first droplet to the second droplet via the droplet interface bilayer; and cause the first droplet to separate from the second droplet. A method of this aspect results in transfer of solvent from the first droplet to the second droplet, whereby the fluid in the first droplet becomes more concentrated and the fluid in the second droplet becomes more diluted. This provides a convenient way of altering the concentration in a fluid droplet within an EWOD device.