Iodine-Functionalized Poly(ester urea)s for Radiopaque Surgical Implants

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Solution Overview

Problem

Amino acid-based poly(ester urea) polymers lack radiopacity, which hinders their use in surgical implants and medical devices where X-ray imaging is necessary for precise placement verification, as conventional methods for enhancing radiopacity often compromise mechanical properties or stability.

Innovation Solution

Development of iodine-functionalized phenylalanine-based poly(ester urea) polymers, where varying the feed ratio of iodine-containing monomers modulates thermal, mechanical, and radiopacity properties, enhancing X-ray contrast without significantly affecting mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiopaque additives are incorporated into polymeric biomaterials, then radiopacity is improved, but mechanical strength and stability deteriorate

Engineering Contradiction:
ImproveradiopacityVSAvoidmechanical strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent combines radiopaque functionality with the polymer matrix through covalent bonding of iodinated monomers during polymerization, creating an integrated composite material where the radiopaque component becomes part of the polymer structure itself rather than a separate additive, thereby maintaining mechanical integrity while achieving radiopacity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention creates a composite polymeric biomaterial system by incorporating iodinated monomers (such as iodinated HEMA or MMA) into the polymer matrix, forming a composite material that simultaneously provides both radiopaque properties and mechanical strength through the synergistic combination of polymer and radiopaque components

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If heavy atom additives are blended with polymers, then X-ray contrast is improved, but blend stability deteriorates

Engineering Contradiction:
ImproveX-ray contrastVSAvoidblend stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent creates asymmetric chemical bonding where iodinated monomers form covalent bonds with the polymer backbone through specific functional groups, establishing an asymmetric and stable chemical structure that prevents phase separation and maintains composition stability while providing consistent X-ray contrast

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention changes the chemical parameter of radiopaque component incorporation from physical mixing to covalent bonding, fundamentally altering how the radiopaque substance is integrated into the polymer matrix, which eliminates blend instability and contrast agent leakage while maintaining X-ray contrast

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If iodine is covalently bonded into polymers, then radiopacity is improved, but mechanical properties deteriorate

Engineering Contradiction:
ImproveradiopacityVSAvoidmechanical properties
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent applies local quality by incorporating iodinated monomers at specific positions within the polymer chain structure, allowing radiopaque functionality to be localized to specific segments while the rest of the polymer matrix maintains its mechanical properties, achieving a balance between radiopacity and mechanical strength

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the concentration and distribution parameters of iodinated monomers in the polymer system, optimizing the ratio of radiopaque component to maintain mechanical properties while achieving sufficient radiopacity for medical imaging applications

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 iodine-functionalized polymers exhibit predictable variations in radiopacity and mechanical properties, providing enhanced X-ray contrast necessary for medical device placement verification while maintaining structural integrity, thus improving the translational potential of these materials.

Implementation Method 1

The ability of an element to attenuate X-rays is correlated with the atomic number of the element to the fourth power. Hence, heavy atoms, including iodine, have been utilized to impart radiopacity into polymers and enhance X-ray contrast.

Methodology Applied
Scientific EffectPhotoelectric absorption: Photoelectric Effect

Data Source

PatentEP3140340B1Radioopaque, iodine functionalized phenylalanine-based poly(ester urea)s
Publication Date: 2019.07.10 THE UNIVERSITY OF AKRON
  • EP3140340B1 patent drawingFigure 1A~1B
  • EP3140340B1 patent drawingFigure 2~3C
  • EP3140340B1 patent drawingFigure 4A~5

AI summary

In one or more embodiments, the present invention provides iodine-functionalized phenylalanine-based poly(ester urea)s (PEUs) (and related methods for their synthesis and use) that are metal free, degradable, radiopaque and suitable for use in surgical implants and other medical devices used within a patient. In one or more embodiment of the present invention 4-Iodo-L-phenylalanine and L-phenylalanine are separately reacted with 1,6-hexanediol to produce two monomers, bis-4-I-L-phenylalanine-1,6-hexanediol-diester (1-IPHE-6 monomer) and bis-L-phenylalanine-1,6-hexanediol-diester (1-PHE-6 monomer). It has been found that by varying the feed ratio of the 1-IPHE-6 and 1-PHE-6 monomers, the copolymer composition may be modulated to predictably create phenylalanine-based PEUs having a wide variation in thermal, mechanical and radiopacity properties. As most medical device procedures require placement verification via fluoroscopic imaging, materials that possess inherent X-ray contrast are valuable for a number of applications.