Functionally Graded 3D Printing for Anatomical Tissue Structures

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Solution Overview

Problem

Current solid freeform fabrication techniques are limited in creating complex, functionally graded materials with localized heterogeneity, particularly for tissue engineering applications, as they struggle to fabricate objects with precise anatomical geometries and controlled biomechanics, and are unable to rapidly produce implants that can grow or regenerate with the patient.

Innovation Solution

A method for specifying and fabricating functionally graded materials through 3-D printing, which involves defining the target object's geometry and phenotypic characteristics, distributing materials anisotropically, and generating vector paths for a compatible fabrication machine, enabling the creation of objects with gradual composition and structure variations, such as cell-seeded photocrosslinkable hydrogels with varying mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional solid freeform fabrication techniques are used to fabricate objects, then manufacturing simplicity is maintained, but manufacturing precision and ability to create functionally graded materials with localized heterogeneity deteriorate

Engineering Contradiction:

Improveprecision of anatomical geometriesVSAvoidcomplexity of fabrication process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fabrication process is segmented into distinct functional modules: a deposition system for material placement, a curing system for material solidification, and a coordination system for synchronizing these operations. This segmentation allows each module to be optimized independently while achieving high manufacturing precision through their integrated operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by pre-planning the deposition and curing sequences before fabrication begins. The coordination system pre-coordinates the deposition and curing operations, allowing the system to anticipate and prepare for upcoming material placement and solidification events, thereby achieving precise anatomical geometries.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If traditional solid freeform fabrication techniques are used, then fabrication speed is maintained, but ability to produce complex functionally graded materials deteriorates

Engineering Contradiction:

Improveability to create functionally graded materialsVSAvoidfabrication rate

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system maintains continuous useful action by overlapping deposition and curing operations. While material is being deposited in one region, the curing system simultaneously solidifies previously deposited material in another region. This continuous coordination allows the system to produce complex functionally graded materials without sacrificing fabrication rate.

Inventive Principle:

Principle #20Continuity of useful action

3Stability of the object's composition

If simple single-material deposition is used, then process simplicity is maintained, but ability to create heterogeneous structures with controlled biomechanics deteriorates

Engineering Contradiction:

Improvecontrolled biomechanicsVSAvoidease of fabrication process

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The system applies local quality by enabling different materials with distinct biomechanical properties to be deposited in specific locations within the object. The coordination system controls which material is deposited where, allowing heterogeneous structures with spatially varying biomechanics to be created. This localized material differentiation achieves controlled biomechanics while maintaining relative ease of manufacture through automated material selection.

Inventive Principle:

Principle #3Local quality

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 production of anatomically precise, stable soft tissue structures with localized heterogeneous biomechanics, allowing for the fabrication of complex geometries like heart valves that can be tailored to individual sizes and properties, facilitating tissue engineering and regeneration.

Implementation Method 1

A method for specifying and fabricating functionally graded materials through 3-D printing

Methodology Applied

Scientific Effect3-D printing: 3D Printing

Implementation Method 2

cell-seeded photocrosslinkable hydrogels with varying mechanical properties

Methodology Applied

Scientific EffectPhotocrosslinking: Photopolymerisation

Data Source

PatentUS10894362B2Method for specifying and fabricating an object, associated apparatus, and applications

Publication Date: 2021.01.19 CORNELL UNIVERSITY

AI summary

A method for specifying and fabricating non-homogeneous, anisotropic, truly functionally graded objects. The objects may have defined spatial heterogeneity (e.g., a gradient in material concentration) with local randomized distributions. This local randomness is designed in such a way that global averaging results in the specified spatial heterogeneity. The fabrication of structures is an additive process in which a material is deposited in defined patterns.