Biodegradable Elastomer Vascular Grafts for Endothelialization

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current vascular grafts, particularly small diameter ones, face challenges such as undesirable long-term patency, inner layer thickening, and vascular narrowing due to limited biocompatibility and mechanical properties, which hinder their effectiveness in replacing blood vessels with low blood flow.

Innovation Solution

A biocompatible and biodegradable elastomer is developed, comprising a polyurethane main chain with a hard segment formed by diisocyanate and chain extender reactions, and a soft segment made from biodegradable oligomers like polycaprolactone diol, polyethylene butylene adipate diol, or polylactic acid diol, with specific molar fractions and diisocyanate types, which forms a vascular graft with tailored mechanical properties and pore structures for endothelialization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If allogenic transplantation grafts are used to provide abundant vascular graft sources, then the availability of graft material is improved, but thrombus formation and immune response occur

Engineering Contradiction:

Improveavailability of graft materialVSAvoidthrombus formation and immune response

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent employs biodegradable elastomers that gradually degrade over time, serving as temporary scaffolds for vascular tissue regeneration. These short-living grafts provide structural support initially, then progressively break down as the patient's own tissue takes over, eliminating the need for permanent foreign materials that cause immune responses and thrombus formation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates composite vascular grafts combining biodegradable elastomer matrices with bioactive components and porous structures. This composite approach integrates multiple functions: structural integrity, cell adhesion promotion, vascularization support, and controlled degradation, while avoiding the harmful effects of traditional non-biodegradable materials.

Inventive Principle:

Principle #40Composite materials

2Strength

If non-biodegradable synthesized vascular grafts are used to ensure mechanical stability, then mechanical strength is improved, but long-term biocompatibility and flexibility deteriorate

Engineering Contradiction:

Improvemechanical strengthVSAvoidlong-term biocompatibility

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent designs vascular grafts with dynamic mechanical properties through biodegradable elastomers that progressively change their characteristics over time. Initially providing high mechanical strength to support the vessel, the material gradually softens and degrades as the regenerated vascular tissue matures, allowing the graft to adapt its mechanical properties to match the natural vessel's evolution.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent utilizes biodegradable elastomers whose molecular weight, degradation rate, and mechanical properties can be precisely controlled through polymerization parameters and composition ratios. By adjusting these parameters, the graft provides adequate initial strength while ensuring predictable degradation and improved long-term biocompatibility as the material breaks down into harmless byproducts.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If small diameter vascular grafts are used to replace blood vessels with low blood flow, then the applicability to specific vessels is improved, but long-term patency and mechanical properties deteriorate

Engineering Contradiction:

Improveapplicability to specific vesselsVSAvoidlong-term patency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs electrospinning technology to create vascular grafts with locally optimized porous structures and surface properties. The nanofiber mat exhibits varying pore sizes, fiber densities, and surface characteristics along different regions of the graft, allowing tailored cell infiltration, vascularization, and mechanical properties specific to small diameter vessel requirements while maintaining long-term patency.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9808556B2Biocompatible and biodegradable elastomer

Publication Date: 2017.11.07 NAT TAIWAN UNIV

AI summary

The present invention provides a biocompatible and biodegradable elastomer, comprising a hard segment and a soft segment. The hard segment is formed by reacting diisocyanate and a chain extender; and the soft segment is comprising a biodegradable oligomer diol, wherein the biodegradable oligomer diol is selected from the group consisting of polycaprolactone diol, polyethylene butylene adipate diol (PEBA diol), poly-L-lactic acid diol (PLLA diol), polylactic acid diol and any combination thereof. The biocompatible and biodegradable elastomer of present invention can be used to produce vascular graft, cell carrier, drug carrier or gene carrier.