2. Definition
Characteristics of biomaterials.
Examples of biomaterials.
Some applications of synthetic materials and modified
natural materials in medicine.
Materials used in body.
Properties of biomaterials.
outline
3. Biomaterials:
The material that are biocompatibility with the living tissues of our
body or to adjust with the tissue of biology.
OR
A non-viable material used in medical device, intended to interact
with biological system.
Biocompatibility:
Physiological State of mutual co-existence between a biomaterial
and the environment such as neither has an undesirable effect on
the other.
OR
It also means that materials described display good or harmonious
behavior in contact with tissue & body fluid.
Definition
4. Bioinert:
No host response to the material.
Bio functionality:
Playing a specific function in physical and mechanical terms.
5. Characteristics of biomaterials
Physical requirements
. Hard materials.
Flexible materials.
Chemical requirements
Must not react with any tissue in the body.
Must be non-toxic to the body.
Long term replacement must not be biodegradable.
16. Mechanical properties include those characteristics of
material that describe the behavior under the action of
external force.
Mechanical properties can be determined by conducting
experimental test on the material specimen.
Mechanical properties determine the behavior of
engineering Material under applied forces and loads. the
response of the material to applied forces will depends on
the type of bonding and structural arrangement of atom and
molecules.
Force applied will lead to deformation and if continued
beyond a certain point will lead to ultimate failure
The force ----- STRESS and
Deformation is known as STRAIN
Mechanical properties
17. Stress:- Force per unit area
Units NM/Sq M or Pascal
Strain:- Change in length per unit original length
The path to failure
Stress & Strain
18. TENSILE STRENGTH/ ULTIMATE TENSILE
STRENGTH -
The maximum stress on the curve before breakage
(N/M2)
YIELD STRESS-
Point at which elastic behaviour changes to plastic
behavior.
BREAKING STRESS
Point at which the substance fails/brakes
19. Stress /Strain
For elastic part of curve or the slope of the elastic
part of the curve
SI unit = pascal (Pa or N/m2 or m−1·kg·s−2).
megapascals (MPa or N/mm2) or
gigapascals (GPa or kN/mm2)
DUCTILITY/ BRITTLENESS- The amount by which a
material deforms (i.e. the strain that occurs) before it
breaks. Represented by %age elongation
or reduction in cross section.
HARDNESS- The ability of the surface of a material to
withstand forces
Young’s modulus E
20. The Yield Point = marks the onset of plastic deformation
Plastic Region = Beyond the yield point, irreversible (plastic)
deformation takes place
Various mechanical properties are:
Elasticity
Plasticity
Toughness
Tensile strength
Yield strength
Ductility
Malleability
Brittleness
Hardness
Fatigue
Wear resistance
21. By thermal properties is meant the response of a
material to the application of heat, as a solid absorb
energy in the form of heat, its temperature rises and its
dimension increases.
The thermal properties of material are essential in order
to evaluate the thermal behavior of solid i.e. their
response to thermal changes, the lowering or rising of
temperature.
The thermal properties are:
heat capacity
thermal expansion
thermal conductivity
Thermal properties
22. thermal stability
specific heat
Melting point
thermal shock resistance
Electrical properties
Material is then ability to permit or resist the flow of
electricity
resistivity
conductivity
dielectric strength
Thermoelectricity
Temperature co-efficient resistance
electrical properties are:
23. The optical properties are:
absorptivity
color
luminosity
photosensitivity
reflectivity
refractive index
scattering
transmittance
electromagnetic radiations
Optical properties
