Moldable Bone Substitute Composite with Plasticizer
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Solution Overview
Problem
Current bone scaffold technologies face challenges in being shapeable and injectable at room temperature, providing high mechanical strength, porosity for bone cell ingrowth, and matching the size and shape of natural bone HA particles, while also controlling hardening speed and maintaining bioactivity.
Innovation Solution
A composite of nanocrystalline hydroxyapatite (HA) combined with a biodegradable polymer and specific plasticizers, allowing for prolonged shapeability and high final strength, with the plasticizer being resorbed to create a porous structure suitable for bone cell growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid porous HA material is used to provide structural support and porosity for bone cell growth, then the mechanical strength and porosity are improved, but the material becomes brittle and requires careful fitting before insertion
Solution Approach 1:
The patent changes the physical state and mechanical properties of the HA material by incorporating biodegradable polymers and plasticizers, transforming it from a rigid, brittle material to a moldable composite that can be shaped at room temperature while maintaining sufficient mechanical strength for load-bearing applications
Solution Approach 2:
The invention creates a composite material system combining HA particles with biodegradable polymers and plasticizers, where each component contributes specific properties: HA provides mechanical strength and bone regeneration, polymer provides elasticity and crack resistance, and plasticizer enables moldability at room temperature
2Ease of operation
If polymer/mineral composite materials are used to decrease brittleness and increase elasticity, then the crack resistance and ease of shaping are improved, but the hardening speed increases making the material too stiff to shape at room temperature
Solution Approach 1:
The patent introduces biodegradable plasticizers as intermediary substances that temporarily reduce the viscosity and stiffness of the polymer matrix, enabling extended shapeability at room temperature. These plasticizers act as mediators between the rigid HA particles and the polymer chains, allowing the composite to be molded without requiring high temperatures while maintaining final mechanical strength
Solution Approach 2:
The invention modifies the rheological parameters of the composite by adding plasticizers, which change the glass transition temperature and viscosity of the polymer matrix, enabling the material to remain moldable at room temperature for extended periods while still achieving adequate hardening for load-bearing applications
3Reliability
If nanocrystalline HA particles are used to match natural bone structure and enhance bioactivity, then the bone cell growth induction is improved, but the material becomes more difficult to process and shape
Solution Approach 1:
The patent incorporates nanocrystalline HA particles into a polymer matrix with added plasticizers, creating a composite that combines the high bioactivity of nanoscale HA with the processability benefits of the polymer-plasticizer system, allowing the nanocomposite to be molded at room temperature without aggregating or losing its nanoscale structure
Solution Approach 2:
The biodegradable polymer and plasticizer act as intermediary matrices that disperse and stabilize nanocrystalline HA particles, preventing aggregation and maintaining the nanoscale structure during processing. This intermediary system allows nanocrystalline HA to be easily incorporated and shaped while preserving its high surface area and bone-inducing 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 composite achieves extended moldability and high mechanical strength, facilitating bone cell growth by mimicking natural bone structure and withstanding mechanical loads, while the porous structure enhances bone ingrowth and bioactivity.
Implementation Method 1
These polymers undergo hydrolysis in the human body, producing non-toxic degradation products
Implementation Method 2
Bone scaffold materials contain a structure and composition, which will trigger the formation of bone when implanted in the human body
Implementation Method 3
The biodegradation speed can be governed by the choice of polymer
Data Source
AI summary
Composites and methods of producing a mouldable bone substitute are described. A scaffold for bone growth comprises nanocrystalline hydroxyapatite (HA), a bioresorbable plasticizer, and a biodegradable polymer. Plasticizers of the invention include oleic acid, tocopherol, eugenol, 1,2,3-triacetoxypropane, monoolein, and octyl-beta-D-glucopyranoside. Polymers of the invention include poly(caprolactone), poly(D,L-Lactic acid), and poly(glycolide-co lactide). Methods of regulating porosity, hardening speed, and shapeability are also described. Composites and methods are described using nanocrystalline HA produced with and without amino acids. The scaffold for bone growth described herein displays increased strength and shapeability.