Electrowetting Microreactor for Bubble-Free Liquid Loading

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Solution Overview

Problem

Microreactors face challenges in handling small volumes of biological samples due to difficulties in loading liquids into wells, including contamination risks and bubble formation in microchannels, which affect analysis accuracy and efficiency.

Innovation Solution

A microreactor design featuring a semiconductor substrate with wells coated by dielectric structures and a cap that utilizes electrowetting phenomena to fill wells with liquid by applying a biasing voltage, preventing bubble formation and ensuring simultaneous filling of all wells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual loading with pipettes is used, then accessibility to wells is enabled, but contamination risk increases and very small volumes cannot be handled

Engineering Contradiction:

Improveaccessibility to wellsVSAvoidcontamination risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces manual mechanical pipetting with an automated electrowetting-based liquid transfer system. The electrowetting mechanism uses electrical fields to control liquid movement, eliminating the need for mechanical contact with the wells and thereby preventing contamination while enabling precise handling of very small volumes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary liquid transfer mechanism that uses electrowetting to move liquids between reservoirs and wells without direct mechanical contact. This intermediary system acts as a mediator between the operator and the sample, maintaining sterility while enabling precise liquid handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If capillary action is used for liquid distribution, then very small volumes can be treated, but bubble formation occurs in microchannels

Engineering Contradiction:

Improvesmall volume handlingVSAvoidbubble formation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent replaces passive capillary action with an active electrowetting-based liquid transfer system. By using electrical fields to drive liquid movement through controlled changes in surface energy, the system eliminates the instability and bubble formation associated with capillary forces while maintaining the ability to handle very small volumes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameters controlling liquid movement from passive capillary forces to active electrowetting forces. By dynamically adjusting the electrical voltage applied to the electrowetting electrodes, the system can precisely control liquid transfer without the bubble formation problems inherent in capillary-based systems.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If electrowetting is used to fill wells, then bubble formation is prevented and simultaneous filling is achieved, but additional voltage application infrastructure is required

Engineering Contradiction:

Improvebubble-free loadingVSAvoidvoltage application infrastructure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the electrowetting electrodes with the existing microreactor substrate or cover glass, integrating the voltage application infrastructure into the device structure itself. This integration reduces the overall system complexity by eliminating separate electrode assemblies and simplifying the electrical connection architecture.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the electrowetting electrodes to serve multiple functions: they control liquid transfer, define well boundaries, and can potentially serve as heating elements or sensing electrodes. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 precise handling of extremely small liquid volumes without mechanical parts and prevents bubble formation, ensuring accurate and efficient loading and analysis by overcoming surface tension and capillary instability issues.

Implementation Method 1

a biasing structure, configured for setting up a voltage between the substrate and the chamber. This structure allows fluid in the chamber above the wells to enter the wells when voltage is applied through the electrowetting phenomena

Methodology Applied

Scientific EffectElectrowetting: Electrowetting

Implementation Method 2

a dielectric structure coating at least the top of the walls

Methodology Applied

Scientific EffectDielectric barrier: Dielectric

Data Source

PatentUS10518264B2Microreactor and method for loading a liquid

Publication Date: 2019.12.31 DISTRETTO TECHCO SICILIA MICRO E NANO SISTEMI S C A R L

AI summary

A microreactor includes: a substrate (2; 102; 202) made of semiconductor material; a plurality of wells (5; 105; 205) separated by walls (6; 106; 206) in the substrate (2; 102; 202); a dielectric structure (7; 107; 207a, 207b) coating at least the top of the walls (6; 106; 206); a cap (3; 103; 203), bonded to the substrate (2; 102; 202) and defining a chamber (10; 110; 210) above the wells (5; 105; 205); and a biasing structure (2, 8, 13; 102, 108, 113; 202, 208a, 208b, 213), configured for setting up a voltage (VB) between the substrate (2; 102; 202) and the chamber (10; 110; 210).