Acoustic Cell Aggregate Formation in Microfluidic Channels

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Solution Overview

Problem

Current methods for forming 2- and 3-D cell aggregates are limited by long cultivation times, uneven sizes, and mechanical accessibility issues, making them unsuitable for standardized, rapid, and large-scale production needed for high-throughput assays, especially in tissue engineering where control over graft size and fragility is crucial.

Innovation Solution

A method using acoustic waves in a channel to form multilayer aggregates by hydrodynamic focusing and acoustic field manipulation, allowing for controlled and programmed generation of cell aggregates with specific dimensions, and enabling the creation of tissue-mimetic constructs without damaging the aggregates during collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cell culture methods (pellet, spheroid, hanging drop culture) are used to generate 2- and 3-D aggregates, then cell aggregates can be formed, but the cultivation time is long and the aggregates are of unequal sizes

Engineering Contradiction:
Improveaggregate size uniformityVSAvoidcultivation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional mechanical culture methods (pellet culture, spheroid culture, hanging drop culture) with an acoustic field-based system. Acoustic radiation forces are used to manipulate and aggregate cells in a controlled manner, enabling rapid formation of uniform-sized aggregates without the time-consuming and size-variable conventional approaches.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameters of the culture system by introducing acoustic fields with specific frequencies and intensities. By adjusting acoustic parameters (frequency, power, chamber geometry), the system achieves precise control over aggregate formation kinetics and final size distribution, dramatically reducing cultivation time while ensuring size uniformity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If cell sheets are removed from culture surfaces, then cell sheets can be harvested, but they contract extensively resulting in reduced graft sizes

Engineering Contradiction:
Improvegraft sizeVSAvoidcell sheet size stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent replaces mechanical handling of cell sheets with acoustic field manipulation. Cells are aggregated and formed into grafts directly within the acoustic chamber using acoustic radiation forces, eliminating the mechanical removal step that causes contraction. This allows harvest of full-sized grafts without size reduction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acoustic field acts as an intermediary that holds and shapes cells during the aggregation process. Instead of mechanically removing fragile cell sheets, the acoustic field maintains cells in a controlled state, allowing formation of grafts at their full intended size before harvest.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If cell sheets are handled manually, then cell sheets can be manipulated, but the fragility of cell sheets makes handling difficult

Engineering Contradiction:
Improvehandling easeVSAvoidcell sheet mechanical strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent replaces manual mechanical handling with acoustic field manipulation. Acoustic radiation forces gently trap, transport, and position cell aggregates without physical contact, eliminating the mechanical stress and fragility issues associated with manual handling of cell sheets.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If conventional automated cell culture systems are used, then scale-up can be achieved, but mechanical accessibility is difficult and standardization is limited

Engineering Contradiction:
Improveproduction scaleVSAvoidmechanical accessibility
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical automated culture systems with an acoustic field-based platform. The acoustic chamber provides direct access to cell aggregates for harvesting and manipulation, eliminating the need for complex mechanical retrieval systems while enabling scalable production through array configurations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acoustic chamber serves multiple functions: cell aggregation, graft formation, and easy access for harvesting. This multi-functionality simplifies the overall system design compared to conventional automated systems that require separate mechanisms for each operation, improving both accessibility and standardization.

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 the rapid and controlled formation of 2- and 3-D cell aggregates, allowing for the creation of compact, tissue-mimetic constructs even in microgravity conditions, facilitating handling and scale-up in tissue engineering applications.

Implementation Method 1

The present invention provides a method of forming a multilayer aggregate of objects in a channel... manipulating micron and submicron sized particles can be accomplished using an acoustic force, Fa = V e> k à sin (2ky), generated by an acoustic stationary field

Methodology Applied
Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Implementation Method 2

The standing wave may occur when the thickness of the chamber w and the acoustic wavelength λ are related as shown in the following equation: w = nλ/2 where n is the number of nodes created in the thickness of the chamber. Particles subjected to this force field acoustic variable in thickness, may be pushed to the nodes or antinodes of the standing waves

Methodology Applied
Scientific EffectAcoustic standing wave: Resonance

Implementation Method 3

A method using acoustic waves in a channel to form multilayer aggregates by hydrodynamic focusing and acoustic field manipulation

Methodology Applied
Scientific EffectHydrodynamic focusing:

Data Source

PatentEP2812428B1Method of forming a multilayer aggregate of objects
Publication Date: 2018.07.25 CENT NAT DE LA RECH SCI (C N R S)
  • EP2812428B1 patent drawingFigure 1~3
  • EP2812428B1 patent drawingFigure 4~5
  • EP2812428B1 patent drawingFigure 6~7

AI summary

A method of forming a multilayer aggregate (120) of objects (O) in a channel (2) comprising a liquid (L), said method comprising: a) providing objects (O) at first (50) and second (60) superposed regions of the channel (2), b) obtaining first (110) and second (111) aggregates of objects (O), optionally by applying transverse acoustic waves, preferably stationary waves, within each region to objects (O), and c) bringing said first (110) and second (111) aggregates into contact to form said multilayer aggregate (120) of objects (O) by submitting said first (110) and second (111) aggregates to: - gravity in absence of acoustic waves, or to - acoustic waves, optionally stationary waves, inducing displacement of said first (110) and second (111) aggregates toward each other.