Cryogenic Prototyping for Tissue-Engineering Scaffold Porosity

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Solution Overview

Problem

Current methods for fabricating tissue-engineering scaffolds struggle to create three-dimensional structures with controlled micro- and macroporosity, limiting their ability to mimic the complex architectures of native tissues and provide customized pore sizes and orientations necessary for effective cell growth and tissue regeneration.

Innovation Solution

The method employs cryogenic prototyping, where polymer solutions are dispensed into a reaction chamber at temperatures below the solvent's freezing point, allowing for controlled phase separation and subsequent freeze-drying to create scaffolds with varied micropore sizes and orientations, and macroporous structures defined by temperature gradients and deposition paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fabrication methods (particulate leaching, fiber bonding, solvent casting) are used, then scaffolds can be produced with simple macro-architectures, but the micro- and macro pore size, geometry and connectivity cannot be well controlled

Engineering Contradiction:

Improvepore size and geometry controlVSAvoidscaffold structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The scaffold fabrication process is segmented into multiple rapid prototyping steps, where each layer is built sequentially with precise control over pore geometry. The method divides the continuous scaffold structure into discrete layers that can be independently controlled, allowing different pore sizes and connectivities in different regions to match specific tissue engineering requirements

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention implements local quality control by enabling different pore sizes, shapes, and connectivities in different regions of the scaffold. The rapid prototyping approach allows customization of micro- and macro-architecture at specific locations within the scaffold, matching the heterogeneous structure of native tissues such as bone with cortical and cancellous regions

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If scaffolds are fabricated with homogeneous microstructures, then manufacturing is simplified, but the ability to mimic complex native tissue architectures with different layers and functions is lost

Engineering Contradiction:

Improvetissue-specific structure customizationVSAvoidfabrication process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention introduces dynamic control over scaffold architecture through computer-controlled rapid prototyping. The fabrication process can dynamically adjust pore size, shape, and distribution layer by layer, allowing the scaffold to adapt its structure to match different tissue types (bone, cartilage, skin) and their specific functional requirements, while maintaining a unified manufacturing platform

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If rapid prototyping methods are used to create complex 3-D scaffolds, then controlled micro- and macroporosity can be achieved, but the process complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvemicro- and macropore structure controlVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical assembly processes with computer-controlled material deposition. Instead of manually assembling complex porous structures, the system uses automated rapid prototyping to directly fabricate the scaffold with precise control over pore architecture, reducing manual intervention while maintaining high manufacturing precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 the fabrication of scaffolds with tailored micro- and macroporous structures, enhancing cell infiltration, vascularization, and tissue regeneration by providing the necessary structural environment for different cell types, improving the efficacy of tissue engineering applications.

Implementation Method 1

dispensing a first polymer solution into a reaction chamber at a temperature which is at or below the freezing point of the solvent

Methodology Applied

Scientific EffectFreezing: Freezing

Implementation Method 2

allowing for controlled phase separation and subsequent freeze-drying to create scaffolds with varied micropore sizes and orientations

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 3

subsequent freeze-drying to create scaffolds with varied micropore sizes and orientations

Methodology Applied

Scientific EffectFreeze-drying: Freeze Drying

Implementation Method 4

macroporous structures defined by temperature gradients and deposition paths

Methodology Applied

Scientific EffectTemperature gradient: Temperature Gradient

Data Source

PatentUS8557163B2Manufacturing three-dimensional scaffolds using cryogenic prototyping

Publication Date: 2013.10.15 NANYANG TECH UNIV

AI summary

The present invention refers to a method of fabricating a three dimensional scaffold suitable for tissue-engineering having a controlled micro- and macroporous structure using cryogenic prototyping. The present invention also refers to scaffolds obtained by the method of the present invention and to their use.