Dr. Alagiriswamy A A, (M.Sc, PhD, PDF)

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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 1
Mar. 22/10
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before i proceed

• I refer you to read out this handbook
• Available in our SRM library
• Totally three copies
• Out of three, only one is reference type
• Author Information
• By Dr. Buddy D. Ratner, School of Dentistry and
  Medicine, University of Alabama, Birmingham,
  U.S.A.

"The most thorough textbook available, covering
most aspects of biomaterials science provides
the most up-to-date and in-depth information on
biomaterial developments." --MRS Bulletin,
January 2006
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My lectures are on the web.
All my lectures are in PowerPoint and will be on
my web site www (click on Lectures).
Please download them before class, so you
dont have to take many notes in class.
Ill be creating/continually modifying them as
the term progresses, so its best not to download
them all the first day, and/or unless specified
in advance.
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More than a multi-disciplinary Field

• Bioengineers
• Material Scientists
• Immunologists
• Chemists
• Biologists
• Surgeons
• others

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A Little History on Biomaterials

• Romans, Chinese, and Aztecs used gold in
  dentistry over 2000 years ago, Cu not good.
• Ivory wood teeth
• Aseptic surgery 1860 (Lister)
• Bone plates 1900, joints 1930
• Turn of the century, synthetic plastics came into
  use
• WWII, shards of PMMA unintentionally got lodged
  into eyes of aviators
• Parachute cloth used for vascular prosthesis
• 1960- Polyethylene and stainless steel being used
  for hip implants

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• Why Biomaterials ????

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Background

• During the last two decades, significant advances
  have been made in the development of
  biocompatible and biodegradable materials for
  medical applications.
• In the biomedical field, the goal is to develop
  and characterize artificial materials or, in
  otherwords, spare parts for use in the human
  body to MEASURE, RESTORE and IMPROVE physical
  functions and enhance survival and quality of
  life

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CLASSIFICATION OF BIOMATERIALS

• First generation INERT
• Do not trigger any reaction in the host neither
  rejected nor recognition
• do not bring any good result
• Second generation BIOACTIVE
• Ensure a more stable performance in a long time
  or for the period you want
• Third generation BIODEGRADABLE
• It can be chemically degraded or decomposed by
  natural effectors (weather, soil, bacteria,
  plants, animals)

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(No Transcript)
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Restoration artificial implantation surgery using
silicone technology
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BIOMATERIALS

• Biomaterials science may be the MOST
  multidisciplinary of all the sciences which
  encompasses aspects of medicine, biology,
  chemistry, engineering and materials science.
• Biomaterials are Non-viable materials used in
  a medical devices intended to interact with
  biological systems D.F. Williams, 1987
• Non-viable - incapable of growing and
  developing independently

What do you mean by the term "Most" ?
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What is the definition of a Biomaterial ?

• Casual definition
• A BIOMATERIAL is a synthetic material used to
  replace part of a living system or to function in
  intimate contact with living tissue.
• Formal definition by Clemson University Advisory
  Board for Biomaterials
• A BIOMATERIAL is a systemically and
  pharmacologically inert substance designed for
  implantation within or incorporation with living
  systems.

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Success of biomaterials

• Dependent on factors engineers/scientists can
  control
• Choice of material
• Geometric design
• Synthesis or manufacturing of biomaterial
• Dependent on factors engineers/scientists cannot
  control
• Surgical technique
• Health and condition of patient
• Post-surgical activities by patient

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Is it derogating ??
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Some interesting physical measurables
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Variable Pore Size in Bone
Is it interesting ????
4µm
220µm
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Micro-evaluation of biomaterials

• Define reliability (r) probability of
  biomaterial failure (f) r 1 f
• May have multiple modes of failure based on
• Body infection
• Implant toxicity
• Inflammation of immune response
• Mechanical failure (strength, stiffness, and
  fatigue)
• Optical/Electrical properties
• Diffusion properties
• Manufacturability
• Density
• Geometric design
• Thus, total reliability (rt) is given by product
  of individual reliabilities r1 (1-f1) rt
  r1r2 rn

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Biomaterials may be considered as metals,
ceramics, polymers, or composites
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Bio-technical terms

• BIOFUNCTIONALITY
• Playing a specific function in physical and
  mechanical terms
• BIOCOMPATIBILITY
• Concept that refers to a set of properties that a
  material must have to be used safely in a
  biological organism
• Synthetic or natural material used in intimate
  contact with living tissue (it can be implanted,
  partially implanted or totally external).
• Biocompatible materials are intended to interface
  with biological system to EVALUATE, TREAT,
  AUGMENT or REPLACE any tissue, organ or function
  of the body
• Biocompatible material features
• Absence of carcinogenicity (the ability or
  tendency to produce cancer)
• Absence of immunogenic (absence of a recognition
  of an external factor
• which could create rejection)
• Absence of teratogenicity (ability to cause birth
  defects)
• Absence of toxicity

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Biocompatibility is primarily a surface
phenomenon
Testing specimens

• Rabbits ear, skin, pyrogen
• Guinea Pigs skin, esp C_at_
• Mice genotoxicity
• Horseshoe Crab endotoxins
• Pig implant
• Bacteria - genotoxicity
• Test actual elutants extracts
• People long term

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Some more BIO-TECHNICAL terms

• Bioactivity - Evolving concept
• The characteristic that allows the material to
  form a bond with living tissue (Hench, 1971)
• The ability of a material to stimulate healing
  and trick the tissue system into responding as if
  it were a natural tissue (Hench 2002).
• Advantages Bone tissue implant interface,
  enhanced healing response, extends implant life
• Biodegradability
• Breakdown of implant due to chemical or cellular
  actions
• If timed to rate of tissue healing transforms
  implant to scaffold for tissue regeneration
• Negates issues of stress shielding, implant
  loosening, long term stability

what about biodurability, bioavailability,
bioinert ?????????????
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Some examples of biomaterials
Where is chitra Triunal (trivandrum)??
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Understanding the ideas of each lecture REQUIRES
the knowledge of the previous lectures.

• In the past, people who have skipped a lot of
  classes have received very bad grades.
  Conversely, people whove come to most or all of
  the classes nearly always receive As and Bs.
• Find out the secrets of how to become a rich or a
  fast learner ?????????

If you keep up, you wont end up looking like
this hour before the commencement of the classes.
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Are you compatible with this class??