Download Biological Properties

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 material
Result
Example
Toxic
Tissues death
Most of the Metals
Nearly Inert
Fibrous tissue formation
Most of the Ceramics like
Alumina and Zirconia
Bioactive
Surface-tissue interaction at
the interface
Hydroxyapatite, Bioglass
Degradable
Substitution 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
Property
Metal
Polymer
Ceramic
Biocompatibility
Low
Toxic products
Intermediate
Can be toxic
High
Mostly bioactive
and non-toxic
Mechanical
High
intermediate
Low
Processability
intermediate
High
Low
Classification of application of
materials in Biomedical Engineering
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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
rejection
Biomaterial
Biocompatibility
Biocompatibility 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 cells
2. 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:
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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
Optical
sensors
Pressure
sensors
Physical
sensors
Temperature
sensors
Magnetic
sensors
Acoustic
sensors
Biosensors
Gas sensors
Chemical
sensors
Humidity
sensors
Ionic sensors
Biochemical
sensors
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
Materials for
biosensors
Synthetic
polymers
Hydrogels
Natural
polymers
Biological
materials
Ceramics
Metals
Biological
tissues
Piezoelectric Sensors
Bioceramics
• Calcium phosphates: hydroxyapatite, tricalcium
phosphate
• Alumina
• Zirconia
• Glass-Ceramics
• Bioglass
• Clays and LDHs( Layered Double Hydroxide)
• Ferromagnetic bioceramics
• Carbons
Types of bioceramics
Forms
Structure
application
Powder and granules
Polycrystalline
Amorphous
Filler, tissue regeneration and
repair
Coat
Polycrystalline
Amorphous
Semi-Crystal
Tissue bonding, anticoagulation, anti-corrosion
Body
Single crystal
Polycrystalline
Amorphous
Composite
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
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Nearly Inert
Bioactive
Resorbable
Porous
Bioceramics applications
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Orthopedic implants
Dental implants
Grafts and substitutes
Hypodermic devices
Ear implants
Contact lens
Artificial heart valves