1. ABCs of Biomaterials Dr. Alagiriswamy A A, (M.Sc, PhD, PDF)
Asst. Professor (Sr. Grade),
Dept. of Physics, SRM-University,
Kattankulathur campus,
Chennai
ABCs of Biomaterials
UNIT III
Lecture 2
Mar. 25/10
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2. Interesting cues
A simple “THANK YOU” makes a difference
Display supportive behavior to ensure team success
To keep up efficiency limit your work : - FATIGUE
Key to people related problems is always with you
Betrayal, however small, causes displeasure among staffs
Courtesy : - The Hindu, page 1 -6, opportunities, Mar. 24/10
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3. Outline of the presentation
CLASSIFICATION OF BIOMATERIALS
COMPARISON OF PROPERTIES OF BIOMATERIALS
EFFECT OF PHYSIOLOGICAL FLUIDS
BIOLOGICAL RESPONSES
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4. TYPICAL BIOMATERIAL APPLICATIONs
a biomaterial should not GIVE OFF its mass unless it is specifically designed to do so
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5. BIOMATERIALS- CLASSIFICATION
Bioinert Biomaterials : -minimal interaction with the tissue
stainless steel, titanium, alumina, partially stabilized zirconia, and ultra high molecular weight polyethylene
Bioactive Biomaterials : - maximum functionality
synthetic hydroxyapatite [Ca 10 (PO4)6(OH)2], glass ceramic and bioglass
Bioresorbable Biomaterials : - maximum absorption and dissolves leads to the maximum advantage of bones
tricalcium phosphate [Ca3(PO4)2] and polylactic- polyglycolic acid copolymers
rely on surface, mechanical, thermal properties atleast
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6. SURFACE PROPERTIES Surface Energy What is a true surface ?
At the surfaces, there are asymmetric forces involved
Quantification of disruption of bonds/surfaces
Metals/ceramics:- high surface energies ranging from 102 to 104 ergs/cm2.
Polymers/plastics have much smaller surface energies, usually <100 ergs/cm2.
Adsorption of gases and/or organic species makes the quantification tougher even for simpler systems.
Why don’t you think off some acute remedies????????????????????????
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7. Surfaces and Interfaces
“A region of space in which the system
undergoes transition from one phase to
another”
Liquid/Gas
Liquid/Liquid
Solid/Solid
Solid/Gas
Surface: Region between condensed phase (S or L)
and a gas phase
Interface: Region between two condensed phases
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9. Some more surface properties
Contact Angle
quantitative measure of the WETTING of a solid by a liquid
angle at which a liquid/vapor interface MEETS the solid surface
Three interfaces determines the interactions and so angle
used to discriminate hydrophobics and hydrophilics
Contact angle analysis characterizes the wettability of a surface by measuring the surface tension of a solvent droplet at its interface with a homogenous surface
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10. Goniometry
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11. Factors: surface roughness, adsorption, contamination
Contact angle analysis
Young-Dupree equation depicts at equilibrium conditions
s/g, s/l and l/g are the interfacial free energy between the solid and gas; solid and liquid, liquid and gas respectively and  the contact angle
s/g = s/l + l/g cos 
The wetting characteristic can be generalized as
 = 0, complete wetting ;
  0  900, partial wetting ;
 > 900 , no wetting.
Factors: surface roughness, adsorption, contamination
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12. Critical Surface Tension: -
Surface tension is a measurement of the cohesive energy present at an interface
bulk of a liquid are balanced by an equal attractive force in all directions
Molecules on the surface of a liquid experience an imbalance of forces
Polar liquids, such as water, have strong
intermolecular interactions and thus high
surface tensions.
If temperature increase, surface energy
decreases, system collapses
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13. Critical surface tension by Zisman plot
A concept developed in the 1960`s by Walter Zisman
The surface tension of a liquid that would completely wet the solid of interest.
Surface energy of surface can be expressed by critical surface tension.
Low critical surface tension means that the surface has a low energy.
Measure on one surface for a series of liquids varying in surface tension
Plot cos  Vs lv.
Extrapolate to cos  = 1.0 ( = 0˚ )
Define c at cos  = 1.0 ( = 0˚ )
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14. Determination of Surface Energy Using Contact Angle (Zisman Plot)
Contact angle measurement
of a solid with various liquids
of known surface tension
Cos  = 1 – b(l - c)
Cos 
 – Contact angle
b – 0.03 –0.04
l – Surface tension of liquid
c – Critical surface tension 1
Extrapolate curve to Cos  = 1, obtain c , characteristic of
Surface Energy
(Adamson, 1997)
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15. how to figure it out the biocompatibility, bioinert issues???
Critical Surface Tension
Why critical surface tension is so important
Thrombus formation
Blood clotting studies
Other tissue related studies
how to figure it out the biocompatibility, bioinert issues???
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16. Examples of interfacial phenomenon
Food
Texture
Structure
- Creaming
- Settling
Paper
Quality
Uniformity
Strength
Paints
Opacity
Color Strength
Gloss
Viscosity
Microelectronics
Chemical Mechanical Polishing (CMP)
Stabilization / dispersion of particulate systems impact the performance of industrial processes.
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17. Sincerely
AAA
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