Multichannel PVA/GO Nerve Conduit via Directional Freeze Casting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current peripheral nerve conduits with single tubular structures are inadequate for repairing large nerve gaps, as they fail to mimic the natural multi-hollow lumen structure, leading to incomplete nerve function recovery, and the fabrication of aligned nanofiber scaffolds is complex and limited by material selection.

Innovation Solution

A method involving directional freeze casting and 3D printing to create aligned and multichannel peripheral nerve conduits using a graphene oxide (GO) and polyvinyl alcohol (PVA) solution, where the solution is frozen in a specific mold with ice pillars growing vertically, resulting in conduits with aligned structures that mimic the natural nerve structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If single tubular structure conduits are used, then the structure is simple to fabricate, but the nerve function recovery is insufficient

Engineering Contradiction:

Improvefabrication simplicityVSAvoidnerve function recovery

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The conduit is divided into multiple hollow lumens (trifoliate, tetrafoliate, or pentafoliate structures) instead of a single tubular structure. This segmentation mimics the natural multi-hollow lumen structure of peripheral nerves, allowing separate guidance of different nerve fascicles and improving nerve function recovery while maintaining fabricability through controlled freezing processes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple hollow lumens are nested within a single conduit structure, with each lumen capable of independently guiding nerve regeneration. The nested configuration allows complex multi-channel functionality while using a unified fabrication approach through directional freezing of the precursor solution

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If aligned nanofiber scaffolds are fabricated using electrospinning, then the axon elongation is guided and boosted, but the fabrication process is complicated and time-consuming

Engineering Contradiction:

Improveaxon elongation guidanceVSAvoidfabrication complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrospinning process is replaced with a directional freeze-casting method. Instead of using electrical fields to align fibers, the invention uses controlled freezing to induce self-assembly of nanofibers along the freezing front, achieving aligned nanofiber structures through thermal gradients rather than electrical fields, thereby simplifying the fabrication process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes the phase transition of water during freezing to create aligned nanofiber structures. By controlling the freezing direction and temperature gradient, ice crystals form and guide the self-assembly of PVA and GO nanofibers along the freezing front, creating aligned structures without complex electrospinning equipment

Inventive Principle:

Principle #36Phase transitions

3Adaptability or versatility

If traditional fabrication methods are used, then the material selection is limited, but the hydrogel applicability is restricted

Engineering Contradiction:

Improvematerial selection rangeVSAvoidhydrogel applicability

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention combines PVA (polyvinyl alcohol) with GO (graphene oxide) to create a composite hydrogel system. This composite approach allows the use of hydrogels that were previously not applicable to aligned fiber fabrication, as the freeze-casting process accommodates the unique properties of hydrogel composites, expanding material selection while maintaining ease of manufacture

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the physical parameters of the fabrication process by using controlled freezing temperatures and rates, allowing hydrogel materials to be processed into aligned structures. By adjusting freezing parameters rather than relying on electrospinning parameters, a broader range of hydrogel materials becomes applicable

Inventive Principle:

Principle #35Parameter changes

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

The conduits facilitate directed axonal extension and Schwann cell migration, enhancing nerve repair by providing a multichannel structure that guides reinnervation and promotes regenerative capacity, with improved mechanical properties due to anisotropic polymer chain alignment.

Implementation Method 1

directional freeze casting

Methodology Applied

Scientific EffectFreezing: Freezing

Implementation Method 2

The ice nucleus would grow vertically and generate ice pillars in parallel

Methodology Applied

Scientific EffectCrystallisation: Crystallisation

Implementation Method 3

the frozen samples were freeze-dried

Methodology Applied

Scientific EffectFreeze drying: Freeze Drying

Data Source

PatentUS20250018086A1Aligned and multichannel peripheral nerve conduit and preparation method thereof

Publication Date: 2025.01.16 THE HONG KONG UNIV OF SCI & TECH

AI summary

An aligned and multichannel peripheral nerve conduit, including Polyvinyl alcohol (PVA) and graphene oxide (GO) with aligned and multichannel design for peripheral nerve repair. 3D printing technology with assembly is utilized to make a specific mold to get a multichannel design to mimic natural peripheral nerves. Directional freeze casting is used to form an aligned PVA/GO hydrogel structure to guide cell growth.