Bioactive Glass Beads with Amorphous Shield for Scaffold Strength
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Solution Overview
Problem
Current porous bioactive glass scaffolds face challenges due to low strength, poor handleability, and rapid crystallization when heated, making it difficult to create commercially available, amorphous, and rigid scaffolds for tissue repair and regeneration, especially for clinical use in orthopedic applications.
Innovation Solution
A method involving a glass or glass-ceramic bead with an internal porous scaffold microstructure surrounded by an amorphous shield, which increases strength and flowability, allowing for enhanced degradability and tissue growth, using a process that involves crushing bioactive glass particles, forming agglomerates, and sintering them with rapid heating and cooling to suppress crystallization and create a porous, shielded structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If highly porous structures are used to promote tissue growth and healing, then tissue penetration and surface area for reaction are improved, but strength and handleability deteriorate causing the scaffolds to easily break and become ineffective
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the interior maintains high porosity for tissue penetration while the exterior develops a dense crystalline shell for strength. The rapid cooling process creates different microstructures in different regions of the same particle - amorphous porous interior and crystalline exterior - allowing each region to fulfill its specific function.
Solution Approach 2:
The invention creates a composite microstructure within each glass particle, combining amorphous porous material (for bioactivity and tissue penetration) with crystalline material (for strength and handleability). This composite structure resolves the contradiction between porosity and mechanical strength by integrating two materials with complementary properties.
2Manufacturing precision
If silicate based bioactive glasses are heated above glass transition temperature to create porous scaffolds, then porosity and tissue penetration are improved, but crystallization occurs rapidly making viscous sintering difficult
Solution Approach 1:
The patent applies the skipping principle by rapidly heating the glass particles through the glass transition temperature range and immediately quenching them, thereby rushing through the temperature zone where crystallization would normally occur. This rapid thermal processing allows the formation of porous structure while avoiding the crystallization that would otherwise occur during slow heating.
Solution Approach 2:
The invention utilizes phase transitions by controlling the thermal history of the glass particles to transition from a crystalline state (in the raw material) through the glass transition to an amorphous state, then rapidly cooling to lock in the amorphous porous structure. The controlled phase transition enables formation of the desired microstructure while preventing unwanted crystallization.
3Strength
If large glass particles (>500 μm) are used to maintain structural integrity, then strength is improved, but conversion to hydroxyapatite takes years due to small surface area to mass ratio
Solution Approach 1:
The patent applies segmentation by dividing the particle into two functional zones: an amorphous porous interior that provides high surface area for rapid bioactive glass to hydroxyapatite conversion, and a crystalline exterior shell that provides mechanical strength. This segmentation allows the particle to simultaneously achieve fast degradation (weeks instead of years) and adequate strength.
Solution Approach 2:
Different regions of the particle are given different properties - the interior is made amorphous and porous for rapid reaction with body fluids, while the exterior is made crystalline for structural support. This local differentiation resolves the contradiction between size-related strength and surface area-driven conversion rate.
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 results in a scaffold that is stronger, more handleable, and promotes faster tissue regeneration by maintaining porosity and surface area for reaction with body fluids, reducing conversion time to hydroxyapatite and improving clinical usability by minimizing immune response and handling issues.
Implementation Method 1
heating and rapidly cooling the agglomerates to suppress crystallization and form an amorphous shield
Implementation Method 2
the surface area available for reaction with body fluids is relatively large and penetrates throughout the entire scaffold
Data Source
AI summary
A glass, glass ceramic, or ceramic bead is described, with an internal porous scaffold microstructure that is surrounded be an amorphous shield. The shield serves to protect the internal porous microstructure of the shield while increasing the overall strength of the porous microstructure and improve the flowability of the beads either by themselves or in devices such as biologically degradable putty that would be used in bone or soft tissue augmentation or regeneration. The open porosity present inside the bead will allow for enhanced degradability in-vivo as compared to solid particles or spheres and also promote the growth of tissues including but not limited to all types of bone, soft tissue, blood vessels and nerves.