Engine-and-Cargo EWOD Droplet Manipulation for Organic Solvents

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Solution Overview

Problem

Conventional microchannel-based microfluidic devices face challenges such as clogging, cross-contamination, and difficulty in handling non-polar or polar aprotic solvents due to their poor movability in electrowetting-on-dielectric (EWOD) devices, limiting their application in organic synthesis.

Innovation Solution

An 'engine-and-cargo' system is introduced, where a droplet of ionic liquid with electrowetting properties acts as the 'engine' to move and encapsulate a droplet of a non-movable organic solvent, enabling its manipulation and use in EWOD devices for chemical reactions like esterification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional microchannel-based microfluidic devices are used for organic synthesis, then continuous flow reactions can be performed with high efficiency, but channel clogging occurs and hydrodynamic pressure becomes unstable

Engineering Contradiction:

Improvereaction efficiencyVSAvoidhydrodynamic pressure stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical continuous flow system with a droplet-based digital microfluidic system. Instead of relying on continuous liquid flow through channels, the system uses discrete droplets that are manipulated individually, eliminating the mechanical pumping and pressure control issues that cause channel clogging and pressure instability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If EWOD devices are used to manipulate fluids, then droplet-based flow prevents cross-mixing and cross-contamination, but non-polar or polar aprotic solvents cannot be moved due to poor electrowetting properties

Engineering Contradiction:

Improvecross-contamination preventionVSAvoidsolvent compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary substance - a movable droplet containing an electrowetting-active component - that acts as a mediator to transport non-movable organic solvents. This intermediary droplet can be manipulated by EWOD fields while carrying the non-movable solvent, thus enabling movement of solvents that would otherwise be incompatible with EWOD manipulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a nested droplet structure where a movable droplet (containing electrowetting components) encapsulates a non-movable organic solvent droplet. The inner non-movable droplet is contained within the outer movable droplet, allowing the inner droplet to be transported被动ively by the active manipulation of the outer droplet.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If DEP force is used to operate non-movable fluids, then some organic solvents can be manipulated, but extremely higher voltage is required and fluids must have specific dielectric properties

Engineering Contradiction:

Improvefluid manipulabilityVSAvoidvoltage requirement

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent uses an intermediary movable droplet as a mediator to transport non-movable solvents. Instead of directly applying high-voltage DEP forces to the non-movable solvent, the system applies standard EWOD voltages to the intermediary droplet, which then passively carries the solvent. This indirect approach eliminates the need for extremely high voltages and specific dielectric properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 the successful on-chip performance of chemical reactions with organic solvents, demonstrating high conversion rates and efficient reaction kinetics, and paves the way for combinatorial synthesis by overcoming the limitations of solvent movability in EWOD devices.

Implementation Method 1

applying a voltage to the surface to move the first droplet towards the second droplet

Methodology Applied

Scientific EffectElectrowetting: Electrowetting

Data Source

PatentUS11779927B2On-chip organic synthesis enabled by engine-and-cargo in an electrowetting-on-dielectric digital microfluidic device

Publication Date: 2023.10.10 BOARD OF RGT THE UNIV OF TEXAS SYST

AI summary

A method of moving a solvent without electrowetting properties on an electro-wetting-on-dielectric (EWOD) microfluidic device comprises disposing a first droplet of a first fluid having electrowetting properties on a surface of the EWOD microfluidic device; disposing a second droplet of a second fluid without electrowetting properties on the surface; applying a voltage to the surface to move the first droplet towards the second droplet; contacting the first droplet with the second droplet to form a encapsulated droplet, where the second droplet encapsulates the first droplet.