Bioactive Materials by Wanpeng Cao & Larry L. Hench Sept 20 th 2012 Literature Review By : Leon Valentino Advisor : Prof. Shao-Ju Shih
Bioactive Materialsby Wanpeng Cao & Larry L. Hench
Sept 20th 2012
Literature Review
By : Leon ValentinoAdvisor : Prof. Shao-Ju Shih
Nano Materials and Grain Boundary Engineering Lab 2
Main Objective• To Study about what is:
Tissue attachment General Theory of Biomaterials Bioactivity Bioactive Ceramics Mechanism of Bioactive Bonding Bioactive Coating and Composites
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Tissue attachment of Biomaterials
ImplantHost Tissue Response1. Nearly Inert2. Porous3. Bioactive4. Resorbable
1. Morphological fixation2. Biological fixation3. Bioactive fixation4. Replacement with tissue
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Tissue response to near inert implantHost Tissue Nearly Inert implant
Response
Non-adherent fibrous capsule (mechanical lock)
More reactive
Thicker Non-adherent fibrous
capsule layer
Micromotion
Degradation of implan/tissue
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Tissue response to porous biomaterial implant
Host Tissue Porous biomaterial implantResponse
Ingrowth of tissue into pores (biological fixation)
Good Biological fixation Pore >100-
150
Capable of withstanding more
complex stress
Provide blood supply
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Tissue response to Bioactive MaterialHost Tissue Bioactive MaterialResponse
Series of biophysical and biochemical reaction occur at interface
Mechanically strong chemical interfacial
bond
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Tissue response to Resorbable MaterialHost Tissue Resorbable
MaterialResponse
Resorbable material degrade gradually and replace by natural tissue
Must metabolically accepted
Rate of degradation must equivalent to regeneration rate
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General Theory of Biomaterial by Hench and Ethridge
a) Ideal implant material perform as if it equivalent to host tissue
b) Axiom 1. The tissue at interface should be equivalent to normal host tissue
c) Axiom 2. Response of the material to physical stimuli should be like that tissue it replaces.
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Bioactivity
Bioactive material
Elicit biological response at interface that form bond
Create osteogenesis environment
BioactivityTime for more than 50% of interface
bonded
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Class in bioactive materialsBioactive Material
Class A (Osteoproductive)
Class B (Osteoconductive)
Elicit intracellular response
Elicit extracellular response
Elicit extracellular response
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Bioactive ceramics• Base component in most bioactive glass and
ceramics (traditional) are SiO2, Na2O,CaO and P2O5.
• By comparing composition of SiO2-Na2O-CaO with P2O5 constant, a diagram of bioactivity are like this:
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Bioactive Bonding
Stage 1-5Do not depend on
the presence of tissues.
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Interaction implant-tissue• Extracellular interaction => determined by
surface features (important for protein and collagen adsorption)
• Intracellular interaction => caused by soluble silicon release from glass surface. Soluble silicon => potent mitogen => enhanced alkaline phospatase activity and osteocalcin (product of resorption of bone) release
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Calcium Phosphate Ceramics
Calcium Phosphate
Precipitation
Hydrolysis
Hydrothermal reaction
Sol-Gel
Solid state reaction
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Biological apatite and Synthetic HABiological Apatite (HCA) Synthetic HA
Contains carbonate (3.2-5.8 wt%) Much more Isotropic than biological apatite
Contains minor element (Mg,Na,K) and trace element (Sr,Pb,Ba) and acid phosphate.
Much larger in grain size
Contains organic material which exist in grain boundaries and has large influence to physical-chemical and biological properties
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Bioactive Composite and CoatingBioactive Composites
and Coating
Have much better biomechanical properties than bioactive ceramics
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Bioactive CompositeBioactive Composites
Matrix : Bioactive glasses/glass-ceramicsReinforce : metal fibers or tough
ceramic part
Matrix : biocompatible PolymerReinforce : Bioactive
glass/ceramic particle or fibers
Elastic moduli > bone
Stress shielding
Mechanical properties close to bone
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Bioactive Composite
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Bioactive coating
Bioactive Coating
Solve mechanical limitation for load-bearing application
Use Metals and alumina (medical grade) as susbtrate coated by HA,TCP,Bioglass
Calcium Phospate deposit using HIP, plasma/flame spraying,ion beam sputtering,
sol-gel deposition and RF sputtering
Good for short term stabilization but cannot be used for long term due to deficiencies
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Conclusion• There are many factors influence bioactivity
such as Morphology (surface morphology,pores), composition, mechanical properties,etc.
• To achieve biochemically and biophysically strong interface between host tissues-implant is very important
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Future Work• Produce MBG using Sol-Gel methode for temp
400 C and 600C
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