Monolithic 3D Microfluidic Devices via Sacrificial Template

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Solution Overview

Problem

Current methods for producing three-dimensional microfluidic devices are limited by their complexity, time-consuming processes, and inability to produce monolithic structures with controlled reproducibility and dimensional stability, making them unsuitable for large-scale industrial production.

Innovation Solution

A method involving the use of a sacrificial thermoplastic template, produced through techniques like casting, hot injection, or hot embossing, which is dissolved or melted to create a three-dimensional network of channels within a matrix material, allowing for the production of monolithic microfluidic devices with controlled geometry and improved reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional semiconductor-derived methods are used to produce microfluidic devices, then manufacturing precision can be achieved, but device complexity increases and three-dimensional monolithic structures cannot be produced

Engineering Contradiction:
Improvechannel geometry precisionVSAvoidstructural simplicity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of creating channels by depositing material layers and removing unwanted portions (conventional approach), the invention inverts the process by first creating a complete three-dimensional sacrificial structure that defines the channel spaces, then removing this sacrificial material to leave the desired channel network. This inversion enables monolithic 3D structures while maintaining manufacturing precision.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces a sacrificial structure as an intermediary element that temporarily occupies the space where channels will eventually exist. This intermediary allows the channel network to be formed as a negative impression of the sacrificial structure, enabling complex 3D geometries that would be difficult to achieve with direct fabrication methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If multiplanar structures are produced by successive superimpositions, then three-dimensional channelling is achieved, but production time increases significantly

Engineering Contradiction:
Improvethree-dimensional channellingVSAvoidproduction time
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

The invention merges multiple planar channel structures into a single integrated three-dimensional sacrificial structure before inserting it into the mould. This combining approach allows all channel levels and interconnections to be formed in one piece, eliminating the need for successive superimposition steps and significantly reducing production time while maintaining complex 3D channelling capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If devices are produced by joining separate layers mechanically or by adhesion, then three-dimensional structures are achieved, but monolithic integrity is lost and adhesion imperfections occur

Engineering Contradiction:
Improvethree-dimensional structureVSAvoidmonolithic integrity
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

Instead of joining separate layers to create 3D structures, the invention inverts the approach by creating a complete 3D sacrificial structure first, then forming the final device as a single monolithic piece around this sacrificial template. This eliminates interlayer adhesion interfaces and ensures monolithic integrity throughout the device structure.

Inventive Principle:
Principle #13The other way round (Inversion)

4Manufacturing precision

If conventional methods are used for producing microfluidic devices, then two-dimensional structures can be manufactured, but productivity for large-scale production is limited

Engineering Contradiction:
Improvechannel geometryVSAvoidlarge-scale production capability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention performs preliminary action by creating complete three-dimensional sacrificial structures with all channel geometries and interconnections pre-formed before inserting them into the mould. This preliminary preparation allows for rapid production cycles and enables large-scale manufacturing while maintaining precise channel geometries, as the complex 3D structures are prepared once and then replicated through the moulding process.

Inventive Principle:
Principle #10Preliminary action

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 method simplifies the production of monolithic three-dimensional microfluidic devices, enhances reproducibility, and reduces production time and costs, making it suitable for both laboratory-scale and industrial applications.

Implementation Method 1

A method involving the use of a sacrificial thermoplastic template, produced through techniques like casting, hot injection, or hot embossing, which is dissolved or melted to create a three-dimensional network of channels

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

A method involving the use of a sacrificial thermoplastic template, produced through techniques like casting, hot injection, or hot embossing, which is dissolved or melted to create a three-dimensional network of channels

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2715450B1Method for the fabrication of monolithic three-dimensional microfluidic devices
Publication Date: 2018.07.25 TENSIVE SRL
  • EP2715450B1 patent drawingFigure 1.a
  • EP2715450B1 patent drawingFigure 1.b
  • EP2715450B1 patent drawingFigure 1.c

AI summary

A method is described for producing a microfluidic device (19), which comprises the phases of producing a three-dimensional template (15) of geometry equal to the channelings that is desired to obtain in the device; inserting the template in the desired position into a mould (16), keeping it suspended by at least one of its end; coating said template by immersion in (or deposition of) a material in the liquid phase (or dissolved or dispersed in a solvent) capable of solidifying by means of a chemical reaction or physical transformation, forming a material constituting the body of the final device; and selectively removing the three-dimensional template. In a variant of the method, useful for the production of scaffolds to be inserted into the human body, a porogenic material is added to the liquid precursor or to the precursor solution, such that the material of the solid matrix is characterised by a continuous structure of pores into which it is possible to insert live cells.