Shape Memory Polymer Fabric for Soft Tissue Repair

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Solution Overview

Problem

Existing shape memory polymer technologies face challenges in providing sustained tension across soft tissue ruptures without premature activation during sterilization or surgical procedures, due to their activation temperatures being close to or below body temperature, leading to inadequate strain recovery and limited therapeutic duration.

Innovation Solution

Development of shape memory polymer fabrics with a glass transition temperature above 50 degrees Celsius, allowing for stored strain to be imparted and maintained below activation temperatures during sterilization and surgery, enabling prolonged tension application across soft tissue ruptures by interlacing fibers in periodic arrays or non-woven meshes, ensuring minimal activation during procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If shape memory polymer is used with activation temperature close to or below body temperature, then strain recovery can be activated during surgical procedures, but premature activation occurs during sterilization or storage leading to inadequate strain recovery and limited therapeutic duration

Engineering Contradiction:

Improvetherapeutic durationVSAvoidstrain recovery control

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent changes the activation temperature parameter of the shape memory polymer from close to or below body temperature to above body temperature (glass transition temperature above 50°C). This parameter change prevents premature activation during sterilization and storage while enabling controlled activation when needed for therapeutic application, thus extending therapeutic duration and improving strain recovery control.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If sterilization is performed at high temperature, then complete sterilization is achieved, but activation temperature is exceeded causing recovery of stored strain during sterilization

Engineering Contradiction:

Improvesterilization effectivenessVSAvoidstrain recovery timing

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent raises the glass transition temperature (activation temperature) above 50°C, which is above typical sterilization temperatures. This allows sterilization to be performed effectively without exceeding the activation temperature, preventing premature strain recovery and maintaining the fabric in its temporary shape for later therapeutic use.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If shape memory polymer with low glass transition temperature is used, then activation occurs at body temperature providing therapeutic effect, but activation occurs too early during storage or surgery preventing sustained tension application

Engineering Contradiction:

Improveactivation timing controlVSAvoidtension application duration

Core Design Contradiction:

Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent increases the glass transition temperature to above 50°C, which is above body temperature. This parameter change allows the fabric to be stored and handled without activation, and enables controlled activation only when deliberately heated above the glass transition temperature during the surgical procedure, thereby providing sustained tension application for extended therapeutic periods.

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 solution provides sustained long-term tension across soft tissue ruptures for periods exceeding two months, with minimal activation during surgery and storage, effectively counteracting muscle atrophy and fatty infiltration, while maintaining the fabric's shape memory effect without inducing strain recovery during sterilization.

Implementation Method 1

Shape memory polymers provide the ability to store strain in an installed or 'temporary' shape via a shape memory effect, whereby the stored strain may be recovered by the shape memory polymer to an 'unconstrained' shape, memorized, or original shape via heating or otherwise activating the shape memory polymer.

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Polymer

Implementation Method 2

the collection exhibiting a storage temperature below 40 degrees centigrade and a glass transition temperature at or above 50 degrees centigrade

Methodology Applied

Scientific EffectGlass transition:

Data Source

PatentUS10582998B1Shape memory polymer fabrics

Publication Date: 2020.03.10 MEDSHAPE

AI summary

The disclosure describes a method including manufacturing a shape memory polymer fabric with a collection of shape memory polymer fibers such that the resulting shape memory polymer fabric has a glass transition temperature of greater than 50 degrees centigrade. The method further includes training the shape memory polymer fabric with a pre-determined percentage of strain between an expanded shape and a contracted shape. The method further includes preparing a portion of the shape memory polymer fabric into a shape that is sized to cover two portions of a ruptured soft tissue of an animal with a mean body temperature below 40 degrees centigrade while the fabric has the predetermined percentage of strain stored in the expanded shape.