Capillary Plate Liquid Handling for Low-Volume Sample Dispensing

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Solution Overview

Problem

Handling small liquid samples in the microliter, nanoliter, or picoliter range is challenging due to high surface-to-volume ratio, leading to high sample consumption and long processing times, and droplet microfluidics is not suitable for many applications on multi-well plates.

Innovation Solution

An apparatus with a capillary and a plate having hydrophobic and hydrophilic areas, capable of precise liquid handling through controlled movement and distance adjustment, using sensors to measure and maintain a distance of 0.1 µm to 500 µm between the capillary opening and the plate surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional pipetting robots are used to dispense small liquid volumes, then liquid handling can be automated, but sample consumption is high and processing time is substantial

Engineering Contradiction:

Improveautomation of liquid handlingVSAvoidsample consumption

Core Design Contradiction:

Extent of automationVSLoss of substance

Solution Approach 1:

The capillary is divided into multiple segments or zones with different wettability properties along its length, allowing different liquid volumes to be held in different segments. This enables precise dispensing of small volumes (nL to pL range) without requiring large sample volumes, directly reducing sample consumption while maintaining automation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wettability parameter of the capillary surface is changed through hydrophobic/hydrophilic patterning. By adjusting the wettability parameters at different locations, the system can control liquid retention and dispensing precisely, enabling automated handling of very small liquid volumes with minimal sample consumption

Inventive Principle:

Principle #35Parameter changes

2Extent of automation

If conventional pipetting robots are used for liquid handling, then automation is achieved, but processing time is long

Engineering Contradiction:

Improveautomation of liquid handlingVSAvoidprocessing time

Core Design Contradiction:

Extent of automationVSLoss of time

Solution Approach 1:

Liquid is pre-loaded into the capillary to a specific position using the wettability gradient before dispensing. This preliminary positioning allows for rapid dispensing without requiring complex aspiration/dispensing cycles, significantly reducing processing time while maintaining full automation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The conventional mechanical aspiration and dispensing mechanism is replaced with a wettability-based liquid positioning system. This substitution eliminates the need for repeated mechanical movements and pressure cycling, reducing processing time while preserving automation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If droplet microfluidics is used for small liquid volumes, then screening speed is enhanced and sample volumes are reduced, but droplets are difficult to assess and standard procedures cannot be easily transferred

Engineering Contradiction:

Improvescreening speedVSAvoidease of assessment and procedure transfer

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The system creates a wettability map or model of the capillary surface that can be replicated and used for standard operating procedures. This copying of the wettability pattern information allows standard procedures to be transferred between different capillaries and systems, improving ease of operation while maintaining high screening speed

Inventive Principle:

Principle #26Copying

4Manufacturing precision

If the capillary is positioned very close to the plate surface (0.1 μm to 500 μm distance), then precision liquid handling is achieved, but the system requires complex distance control

Engineering Contradiction:

Improveprecision of liquid handlingVSAvoiddistance control system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The capillary system uses its own wettability properties to automatically position and retain liquid at the correct dispensing location without requiring external sensors or complex control systems. The hydrophobic/hydrophilic pattern acts as a self-positioning mechanism, achieving high precision while reducing device complexity

Inventive Principle:

Principle #25Self-service

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

Facilitates efficient, faster, and more environmentally friendly liquid handling of small volumes by reducing sample consumption and processing time, while maintaining precision and versatility across various liquid types.

Implementation Method 1

a capillary (2) having a first opening (3) and a second opening (4)... configured to receive and/or dispense a liquid from and/or onto the top surface (5) of the plate via the second opening (4)

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the top surface (5) comprising at least one hydrophobic and at least one hydrophilic area

Methodology Applied

Scientific EffectWettability: Wetting

Data Source

PatentEP4711040A1Apparatus, method and use for liquid handling

Publication Date: 2026.03.18 ETH ZURICH

Figure 1a~1b
Figure 2a~2b
Figure 3~4

AI summary

An apparatus for liquid handling, in particular of small liquid volumes, an associated method and use for liquid handling, in particular for receiving and/or dispensing a liquid, the apparatus comprising: a capillary; a plate; means for moving the capillary and/or the plate relative to each other; and a sensor (9).