Microfluidic Reservoir Loading via EWoD Electrode Actuation

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Solution Overview

Problem

Existing microfluidic devices face challenges in efficiently loading multiple aqueous phase reservoirs, particularly due to surface energy issues and difficulties in achieving consistent volume loading across multiple reservoirs.

Innovation Solution

The method involves using a multichannel pipette to load multiple aqueous reagents into an electrowetting on dielectric (EWoD) device with multiple inlet ports on multiple sides, and employing electrode actuation to form virtual paths and reservoirs, thereby preventing backflow and ensuring accurate volume control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a multichannel pipette is used to load multiple aqueous reagents simultaneously, then loading efficiency and productivity are improved, but surface energy issues and backflow problems worsen

Engineering Contradiction:

Improveloading efficiencyVSAvoidvolume accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The device is pre-configured with multiple inlet ports positioned on multiple sides and electrode arrays that can be actuated in specific sequences. Before loading begins, the system is prepared with hydrophobic coatings on internal surfaces and pre-programmed electrode actuation patterns to prevent backflow and ensure accurate volume delivery to each reservoir location.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Different regions of the device are given different surface properties - the inlet ports and internal channels are coated with hydrophobic materials to prevent wetting and backflow, while the reservoir locations have controlled surface energies to ensure proper liquid retention. This local differentiation allows simultaneous multi-channel loading while maintaining volume accuracy for each reservoir.

Inventive Principle:

Principle #3Local quality

2Reliability

If electrode actuation is used to form virtual paths for loading, then backflow prevention is improved, but device complexity increases

Engineering Contradiction:

Improvebackflow preventionVSAvoidelectrode control system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrode array serves multiple functions: it acts as both the actuation mechanism for forming virtual paths during loading and as the manipulation mechanism for droplet operations after loading. The same electrode structure is used to prevent backflow during fluid delivery and to subsequently move and position droplets, eliminating the need for separate control systems and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple inlet ports are positioned on multiple sides of the device, then adaptability and versatility of loading configurations are improved, but manufacturing precision requirements worsen

Engineering Contradiction:

Improveloading configuration flexibilityVSAvoidport positioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The device is segmented into modular components with standardized inlet port interfaces and electrode arrays. Each side of the device can be independently configured with inlet ports at standardized positions, allowing flexible loading arrangements while maintaining manufacturing precision through standardized manufacturing processes. The modular design enables different loading configurations without requiring custom precision manufacturing for each variant.

Inventive Principle:

Principle #1Segmentation

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 enables precise and efficient loading of multiple reservoirs with high accuracy, even for reagents with high surface tension, and reduces the risk of air bubbles and backflow, improving the reliability of microfluidic operations.

Implementation Method 1

The manipulation of droplets by the application of electrical potential can be achieved on electrodes covered with an insulator or a dielectric or a series of insulators or dielectrics. Droplet manipulation as a result of an applied electrical potential is known as electrowetting.

Methodology Applied

Scientific EffectElectrowetting: Electrowetting

Implementation Method 2

Electrokinesis (movement due to electrical signals) occurs as result of (1) a non-uniform electric field that influences the hydrostatic equilibrium of a dielectric liquid (dielectrophoresis or DEP)

Methodology Applied

Scientific EffectDielectrophoresis: Electrophoresis

Implementation Method 3

The minimum voltage applied to balance the electrowetting force with the sum of all drag forces (threshold voltage) is variably determined by the thickness-to-dielectric contact ratio of the insulator/dielectric

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS20250196132A1Loading and formation of multiple reservoirs

Publication Date: 2025.06.19 NUCLERA LTD

AI summary

Provided herein are methods for the controlled filling of multiple reservoirs on a microfluidic device with a defined volume of fluid.