Electro-Wetting Droplet Interfaces for Reliable Ion-Channel Measurements

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Solution Overview

Problem

Existing electro-wetting devices face challenges in reliably forming droplet interfaces between droplets and efficiently making electrical connections for measurements, particularly in the context of studying transmembrane pores and ion channels, due to difficulties in droplet manipulation and inconvenient measurement setups.

Innovation Solution

A method and device for forming droplet interfaces by applying actuation signals to manipulate droplets into proximity and relaxation, using AC and DC potentials, and incorporating sensor electrodes on a second substrate for reliable electrical connections, allowing for controlled droplet manipulation and measurements across droplet interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional EWOD devices are used to manipulate droplets, then droplet movement and positioning can be achieved, but reliable formation of droplet interfaces and efficient electrical connections for measurements are difficult to achieve

Engineering Contradiction:

Improvedroplet interface formation reliabilityVSAvoidmeasurement setup complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is segmented into two separate substrates: a first substrate containing actuation electrodes for droplet manipulation and a second substrate containing sensor electrodes for electrical measurements. This segmentation allows independent optimization of each function, enabling reliable droplet interface formation while simplifying the measurement setup by providing dedicated electrical connection points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Droplets themselves serve as intermediaries that bridge the actuation electrodes on the first substrate and the sensor electrodes on the second substrate. The droplets make electrical contact with both substrates, enabling measurements across droplet interfaces without requiring complex wiring or connection mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If planar lipid bilayers are used to study transmembrane pores, then simplified models of biological membranes can be obtained, but they are difficult to prepare and have short lifetime

Engineering Contradiction:

Improvemembrane preparation easeVSAvoidmembrane lifetime

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

Instead of directly working with planar lipid bilayers, the invention uses droplet interfaces as a copy or alternative model system. The droplet interface bilayer (DIB) formed between two aqueous droplets in a hydrophobic medium replicates the essential features of planar lipid bilayers while being significantly easier to prepare and having extended lifetime through electro-wetting stabilization.

Inventive Principle:

Principle #26Copying

3Reliability

If droplet interfaces are formed using conventional methods, then interfaces between droplets can be created, but the process lacks control and reliability for studying transmembrane pores

Engineering Contradiction:

Improvedroplet interface formation reliabilityVSAvoiddroplet manipulation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention replaces manual or mechanical droplet manipulation methods with electro-wetting actuation. By applying electrical signals to the actuation electrodes on the first substrate, droplets can be precisely controlled to form interfaces with the sensor electrodes on the second substrate, significantly improving reliability while maintaining ease of operation through electrical control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enhances the reliability of droplet interface formation and facilitates efficient electrical measurements, enabling effective studies of transmembrane pores and ion channels with improved scalability and convenience.

Implementation Method 1

the actuation electrodes are capable of electro-wetting the droplets when actuation signals are applied thereto

Methodology Applied

Scientific EffectElectro-wetting: Electrowetting

Implementation Method 2

droplet interfaces between droplets, for example comprising a membrane of amphipathic molecules

Methodology Applied

Scientific EffectAmphipathic molecule self-assembly: Self-Assembly

Data Source

PatentUS12383903B2Droplet interfaces in electro-wetting devices

Publication Date: 2025.08.12 OXFORD NANOPORE TECH LTD

AI summary

Droplet interfaces are formed between droplets in an electro-wetting device comprising an array of actuation electrodes. Actuation signals are applied to selected actuation electrodes to place the droplets into an energised state in which the shape of the droplets is modified compared to a shape of the droplets in a lower energy state and to bring the two droplets into proximity. The actuation signals are then changed to lower the energy of the droplets into the lower energy state so that the droplets relax into the gap and the two droplets contact each other thereby forming a droplet interface. The use of sensing electrodes in the device permit electrical current measurements across the droplet interface. The sensing electrodes can be used for either (i) applying a reference signal during droplet actuation or (ii) recording electrical current measurements. Two or more electrodes are configurable to lyse cells within a droplet positioned over said electrodes.