biological properties issues to address... biomaterials definition different types of interaction...
TRANSCRIPT
Biological Properties
ISSUES TO ADDRESS...
•Biomaterials definition
•Different types of interaction between body and foreign material
•What are main characteristics of a biomaterial
•Types of biomaterials
•Applications of biomaterials
Biomaterials Definition• A multidisciplinary knowledge of studying materials
behavior in the body environment• Any material, natural or synthetic, that comprises
whole or part of a living structure or a biomedical device which performs, enhances, or replace a function that has been lost through disease or injury
Different types of interaction between body and foreign material
Type of foreign materialResultExample
ToxicTissues deathMost of the Metals
Nearly InertFibrous tissue formationMost of the Ceramics like Alumina and Zirconia
BioactiveSurface-tissue interaction at the interface
Hydroxyapatite, Bioglass
DegradableSubstitution of material whit tissue
Tricalcium phosphate, Collagen
What are main characteristics of a biomaterial?
• Biocompatibility• Mechanical properties• Properties regarding to application
Different types of biomaterials
PropertyMetalPolymerCeramic
BiocompatibilityLow
Toxic productsIntermediateCan be toxic
HighMostly bioactive
and non-toxic
MechanicalHigh intermediateLow
ProcessabilityintermediateHigh Low
Classification of application of materials in Biomedical Engineering
• Implants and tissue replacement• Tissue Engineering• Drug delivery systems• Biosensors and medical diagnosis
Implants and tissue replacement
Body Biomaterial
Fibrosis encapsulation Protein attachment Coagulation Mechanical degradation and erosion Undesirable immunological response Biomaterial rejection
BiocompatibilityBiocompatibility is the ability of the materials to
perform in the presence of an appropriate host for a specific application.
Titanium and titanium alloys (Thin surface oxide)Relatively inert good corrosion resistance
Cardiovascular substitutes:Artificial heart valves
• Heart Function : pumping blood to all parts of body• Entrance and outgoing of blood into ventricle heart
is occurring in heart valves
-Tricuspid valve - Pulmonary valve - Mitral valve- Aortic valve
Types of Artificial Heart Valves Natural substitutes(Bioprosthetic Heart Valves)- High biocompatibility and blood compability - Shorter life-time- Grafting problems like out break of disease
Artificial substitutes(Mechanical Heart Valves)- Longer life-time- Stronger mechanical properties- Can be lead to coagulation
Skin Tissue Engineering
Nerve repair
Injectable Scaffolds (Insitu forming)
Cell Source
1. Autologous cells2. Allogenic cells
• Primary cells• Cell-Lines• Stem cells
Stem cells
Drug Delivery Systems• Delivering drug or any other biological agent to a specific part of patients
body with the control of the dosage• Advantages:
– Increasing drugs effectiveness– Preventing from toxic dosages– Decreasing side effects– Preventing drug loss– Controlling drug behavior– Probability of targeted and prolonged release
Biosensors
• The term ‘‘biosensor’’ is used to cover sensor devices in order to determine the concentration of substances and other analytes of biological interest, in some cases even where they do not utilize a biological system directly
Biosensors
Biosensors
• Sensors compared with sense organs of man: - Optical sensors- eyesight - Gas sensors- olfaction - Sensors for pressure, temperature-touch - Acoustic sensors- hearing - Chemical sensors- taste
Materials for biosensors
Piezoelectric Sensors
Bioceramics
• Calcium phosphates: hydroxyapatite, tricalcium phosphate
• Alumina• Zirconia• Glass-Ceramics• Bioglass• Clays and LDHs( Layered Double Hydroxide)• Ferromagnetic bioceramics• Carbons
Types of bioceramicsFormsStructureapplication
Powder and granules PolycrystallineAmorphous
Filler, tissue regeneration and repair
CoatPolycrystallineAmorphousSemi-Crystal
Tissue bonding, anti-coagulation, anti-corrosion
BodySingle crystalPolycrystalline
AmorphousComposite
Tissue regeneration and replacement
Bioceramics advantages over other materials
• Consisting of elements similar to body physiological environment like: Ca, K, P, Na and Mg
• Products of mechanical degradation and chemical dissolution are inert and can be adsorbed through body metabolism
• Strong ionic and covalent bonds and lack of free electrons prevent formation of electrochemical cell
Types of Bioceramics
• Nearly Inert• Bioactive• Resorbable• Porous
Bioceramics applications
• Orthopedic implants• Dental implants• Grafts and substitutes• Hypodermic devices• Ear implants• Contact lens• Artificial heart valves