Bioactive PEEK Spinal Implants via Silane Coupling
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Solution Overview
Problem
Existing materials for spinal implants, such as PEEK, lack bioactivity and osteoproductivity, and conventional methods struggle to combine PEEK with bioactive glass due to reactivity issues, making it difficult to create a composite that meets the structural and mechanical requirements for spinal implants.
Innovation Solution
A method involving blending PEEK particles with bioactive glass, using a polar organic solvent like ethanol, and removing it under vacuum to achieve homogeneity, followed by molding and shaping to create bioactive composite spinal implants with controlled particle sizes and ratios, which are then treated to enhance mechanical and bioactive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods (twin screw extruder) are used to combine PEEK and combeite glass-ceramic, then the materials can be processed, but the high reactivity causes a reaction between PEEK and combeite that forms a material inhibiting extruder functioning
Solution Approach 1:
The patent uses a silane coupling agent as an intermediary substance between PEEK and combeite glass-ceramic particles. This coupling agent modifies the surface of the glass-ceramic particles to reduce their reactivity with PEEK during extrusion processing, preventing the formation of inhibitory reaction products while maintaining the bioactive properties of the composite material.
Solution Approach 2:
The patent modifies processing parameters including reducing extrusion temperature and adjusting screw rotation speeds to minimize thermal and mechanical activation of reactive sites on combeite particles. These parameter changes reduce the intensity of reactions between PEEK and combeite during processing, preventing extruder malfunction while still achieving adequate mixing and composite formation.
2Strength
If PEEK is used for spinal implants, then excellent mechanical properties (Young's modulus of 3.6 GPa, tensile strength of 100 MPa) are achieved, but the material lacks bioactivity, osteoproductivity, and osteoconductivity
Solution Approach 1:
The patent creates a composite material combining PEEK polymer with bioactive combeite glass-ceramic particles. The composite integrates the superior mechanical properties of PEEK with the bioactive, osteoproductive, and osteoconductive properties of combeite, achieving both structural performance and biological functionality in a single implant material.
Solution Approach 2:
The patent incorporates combeite glass-ceramic particles throughout the PEEK matrix to provide localized bioactive properties at the implant-bone interface while maintaining the overall structural integrity and mechanical properties provided by the PEEK base material. This creates regions of different functionality within the composite.
3Adaptability or versatility
If bioactive glass particles larger than one micron are used, then bioactivity is maintained, but the prior art does not provide a method to combine them with PEEK having appropriate structural and mechanical properties
Solution Approach 1:
The patent performs preliminary surface modification of combeite glass-ceramic particles with silane coupling agents before combining them with PEEK. This pre-treatment reduces particle reactivity and improves compatibility with the polymer matrix, enabling successful extrusion processing of composites containing larger bioactive glass particles that maintain their bioactive properties.
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 method produces bioactive composite spinal implants with improved mechanical properties and bioactivity, capable of forming a calcium phosphate layer when immersed in simulated body fluid, facilitating bone integration and regeneration.
Implementation Method 1
The solvent is then removed, such as in vacuo, to yield a homogeneous blend of particles ready for formation of composite shaped bodies
Implementation Method 2
capable of forming a calcium phosphate layer when immersed in simulated body fluid
Data Source
AI summary
Methods of preparing bioactive composites are described. Also described are methods of molding such composites. Shaped bodies comprising bioactive composites are further described.