Bioabsorbable Elastomeric Networks for Implant Fixation
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Solution Overview
Problem
There is a need for new polymer blends that can form non-biodegradable or biodegradable interpenetrating networks suitable for elastomeric implantable devices, particularly for tissue, tooth, and bone replacement, as existing materials lack the necessary elasticity and toughness for dynamic stress environments without causing tissue irritation or mechanical breakdown.
Innovation Solution
The development of semi-interpenetrating networks using bioabsorbable α-amino acid-based linear polymers and di- or poly-functional cross-linkers with hydrolytically degradable functional groups that polymerize upon exposure to an active species, providing increased elasticity and toughness, allowing for in vivo or ex vivo cross-linking to create implantable fixation devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bioabsorbable linear polymers are used to form implantable devices, then biocompatibility and biodegradation are improved, but elasticity and toughness are insufficient for dynamic stress environments
Solution Approach 1:
The patent creates a semi-interpenetrating network composite by combining bioabsorbable linear polymers (PEA, PEUR, or PEU) with cross-linkers containing polymerizable groups. The cross-linkers form a three-dimensional network within the linear polymer matrix, creating a composite material that exhibits both biocompatibility from the linear polymer and enhanced elasticity/toughness from the cross-linked network structure.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the linear polymer by introducing cross-linking. The cross-linking degree, cross-linker concentration, and polymerization conditions are adjusted to optimize the balance between elasticity and biodegradation rate, allowing the material to meet specific mechanical requirements while maintaining biocompatibility.
2Strength
If cross-linkers are added to increase elasticity and toughness, then mechanical strength is improved, but complexity of polymer composition increases
Solution Approach 1:
The patent uses adjustable parameters such as cross-linker concentration (0.1-10 wt%), polymerization time, and initiator type to control the degree of cross-linking. This allows optimization of mechanical properties while keeping the composition relatively simple and the processing conditions controllable.
Solution Approach 2:
The patent introduces polymerization initiators as intermediaries that trigger the cross-linking reaction. These initiators (photoinitiators, redox initiators, or thermal initiators) enable controlled cross-linking without requiring complex processing equipment, simplifying the overall manufacturing process while achieving the desired mechanical enhancement.
3Strength
If cross-linking is performed to create elastomeric network, then elasticity is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent employs photoinitiators that enable cross-linking upon light exposure, allowing for simple and controlled manufacturing. The light-curing process can be performed in situ or during device fabrication without requiring complex equipment, making the manufacturing process straightforward while achieving the desired elastomeric properties.
Solution Approach 2:
The patent replaces traditional thermal or chemical cross-linking methods with photo-initiated cross-linking. This substitution eliminates the need for complex heating equipment or prolonged chemical treatment, simplifying the manufacturing process while effectively creating the elastomeric network structure.
4Duration of action of stationary object
If bioabsorbable polymers are used for implantable devices, then biodegradation is improved, but mechanical breakdown resistance is insufficient under dynamic stress
Solution Approach 1:
The patent creates a semi-interpenetrating network composite by combining bioabsorbable linear polymers (PEA, PEUR, or PEU) with cross-linkers containing polymerizable groups. The cross-linking provides increased elasticity to the composition by imparting a plasticizing effect. After cross-linkers are polymerized, the composition also possesses increased toughness, enabling the material to withstand dynamic stress without mechanical breakdown while maintaining controlled biodegradation.
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 polymer compositions offer enhanced elasticity and toughness, enabling their use in implantable devices such as bioabsorbable stents and internal fixation devices that can withstand dynamic stress while minimizing tissue irritation and mechanical breakdown, with the option for controlled bio-degradation.
Implementation Method 1
cross-linkers that contain one or more hydrolyzable functional groups and that polymerize upon exposure to an active species
Implementation Method 2
cross-linkers that contain one or more hydrolyzable functional groups
Data Source
AI summary
The invention provides elastomeric polymer networks and semi-interpenetrating networks in which a linear PEA, PEUR or PEU polymer is crosslinked by ester or alpha-amino-acid containing cross-linkers that polymerize upon exposure to active species. Bioabsorbable elastomeric internal fixation devices fabricated using such polymer networks and semi-interpenetrating networks are useful for in vivo implant and delivery of a variety of different types of molecules in a time release fashion. Alpha-amino-acid containing ester amide cross-linkers are also provided by the invention.