Photocurable PGSA Elastomers for Biomedical Applications

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Solution Overview

Problem

Biodegradable elastomers used in biomedical applications face challenges in achieving a balance between mechanical strength and degradability, as mechanical strength is proportional to polymer crosslink density, while degradability is inversely proportional, making it difficult to maintain both properties effectively. Additionally, high-temperature curing processes can damage temperature-sensitive components and limit the complexity of shapes that can be achieved.

Innovation Solution

Development of biodegradable elastomeric polymer compositions formed from photocurable poly(glycerol sebacate acrylate) (PGSA) that can be cross-linked at room temperature via photopolymerization, allowing for the adjustment of tensile strength, degradation, and swelling properties by varying the density of acrylate moieties and incorporating hydrogels, enabling the formation of materials with tailored properties suitable for biomedical applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polymer crosslink density is increased to improve mechanical strength, then mechanical strength is improved, but degradability deteriorates

Engineering Contradiction:

Improvemechanical strengthVSAvoiddegradability

Core Design Contradiction:

StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent employs parameter changes by utilizing photopolymerization instead of thermal curing, changing the curing temperature parameter from high (thermal) to low (room temperature/photocurable). This enables the formation of crosslinked structures with controlled density that maintain both mechanical strength and degradability, as the gentler curing process preserves polymer chain mobility and biodegradation pathways while still achieving adequate crosslinking for structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions by employing photopolymerization that occurs at room temperature without requiring the polymer to transition through a melt phase. This avoids the high-temperature curing process that would cause bubble formation and structural defects, enabling the creation of complex three-dimensional shapes with controlled crosslink density that balances mechanical strength and degradability.

Inventive Principle:

Principle #36Phase transitions

2Strength

If high temperature curing is used to achieve acceptable mechanical properties, then mechanical properties are improved, but temperature-sensitive components are damaged

Engineering Contradiction:

Improvemechanical propertiesVSAvoiddamage to temperature-sensitive components

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the thermal curing mechanism with photopolymerization, substituting a chemical/optical process for a thermal/mechanical one. By using photoinitiators that activate upon light exposure, the curing process occurs at room temperature, preserving temperature-sensitive components such as drugs, growth factors, and cells while still achieving the necessary crosslinking density for acceptable mechanical properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If high temperature curing is used to produce materials with acceptable mechanical properties, then mechanical properties are improved, but shape complexity is limited due to bubble formation

Engineering Contradiction:

Improvemechanical propertiesVSAvoidshape complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #36Phase transitions

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 resulting biodegradable elastomers exhibit improved mechanical compliance with biological tissues, adjustable degradation rates, and the ability to maintain mechanical strength without compromising biocompatibility, facilitating their use in various medical and non-medical applications, including tissue engineering and drug delivery systems.

Implementation Method 1

cross-linked at room temperature via photopolymerization

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11458230B2Method comprising contacting tissue with a cross-linkable polyester prepolymer

Publication Date: 2022.10.04 MASSACHUSETTS INST OF TECH

AI summary

The present inventions in various aspects provide elastic biodegradable polymers. In various embodiments, the polymers are formed by the reaction of a multifunctional alcohol or ether and a difunctional or higher order acid to form a pre-polymer, which is cross-linked to form the elastic biodegradable polymer. In preferred embodiments, the cross-linking is performed by functionalization of one or more OR groups on the pre-polymer backbone with vinyl, followed by photopolymerization to form the elastic biodegradable polymer composition or material. Preferably, acrylate is used to add one or more vinyls to the backbone of the pre-polymer to form an acrylated pre-polymer. In various embodiments, acrylated pre-polymers are co-polymerized with one or more acrylated co-polymers.