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?Clinical Sciences: (All the clinical Specialties) density, maxillofacial, neurosurgery, obstetrics and gynecology, ophthalmology, orthopedics, plastic and reconstructive surgery, thoracic and cardiovascular surgery, veterinary medicine and surgery, etc.Science and engineering: (Materials Science) structureproperty relationships of synthetic and biological materials including metals, ceramics, polymers, composites, tissues (blood and connective tissues), etc.Biology and Physiology: Cell and molecular biology, anatomy, animal and human physiology, histopathology, experimental surgery, immunology, etc.Many millions of patients have enjoyed alleviation of pain, increased function and an improved quality of life due to the success of biomedical materials and the implants and devices made from them.Bio-compatibility: Acceptance of an artificial implant by the surrounding tissues and by the body as a whole.Biomaterials are used to make devices to replace a part or a function of the body in safe, reliably economically, and physiologically acceptable manner.Commonplace examples include suture needles, plates, teeth fillings, etc.1- Standard Specifications: Many standard specification tests of both national and international standards organizations (ISO) are now available, which effectively maintain quality levels.Such specifications normally give details for: (a) the testing of certain products, (b) the method of calculating the results (c) the minimum permissible result, which is acceptable.Biomaterial: A synthetic material used to make devices to replace part of a living system or to function in intimate contact with living tissue.A variety of devices and materials are used in the treatment of disease or injury.The worldwide number of implanted devices is in the range of 4 000 000 to 5 000 000 per year.Fields of Knowledge to Develop Biomaterials ?More than 40 different materials are currently used to replace more than 40 different parts of the body.Biomaterials ?Biological Material: A material that is produced by a biological system.??????

 Biomaterials are used to make devices to replace a part or a
function of the body in safe, reliably economically, and
physiologically acceptable manner. A variety of devices
and materials are used in the treatment of disease or injury.
Commonplace examples include suture needles, plates, teeth
fillings, etc.
 More than 40 different materials are currently used to
replace more than 40 different parts of the body. The
worldwide number of implanted devices is in the range of 4
000 000 to 5 000 000 per year.
 Many millions of patients have enjoyed alleviation of pain,
increased function and an improved quality of
life due to the success of biomedical materials and the
implants and devices made from them.
Biomaterials
 Biomaterial: A synthetic material used to make
devices to replace part of a living system or to
function in intimate contact with living tissue.
 Biological Material: A material that is produced by
a biological system.
 Bio-compatibility: Acceptance of an artificial
implant by the surrounding tissues and by the body
as a whole.
Fields of Knowledge to Develop Biomaterials
 Science and engineering: (Materials Science) structureproperty relationships of synthetic and biological
materials including metals, ceramics, polymers,
composites, tissues (blood and connective tissues), etc.
 Biology and Physiology: Cell and molecular biology,
anatomy, animal and human physiology, histopathology,
experimental surgery, immunology, etc.
 Clinical Sciences: (All the clinical Specialties) density,
maxillofacial, neurosurgery, obstetrics and gynecology,
ophthalmology, orthopedics, plastic and reconstructive
surgery, thoracic and cardiovascular surgery, veterinary
medicine and surgery, etc.
Uses of Biomaterials
Uses of Biomaterials Example
Replacement of diseased and
damaged part
Artificial hip joint,
kidney dialysis machine
Assist in healing Sutures, bone plates and screws
Improve function Cardiac pacemaker, intraocular lens
Correct functional abnormalities Cardiac pacemaker
Correct cosmetic problem Mastectomy augmentation,
chin augmentation
Aid to diagnosis Probes and catheters
Aid to treatment Catheters, drains
Type of biomaterial
Materials Advantage Disadvantage Example
Polymers (nylon,
silicon Rubber,
polyester, PTFE,
etc)
Resilient
Easy to
Fabricate
Not strong
Deforms with
time
May degrade
Blood vessels,
Sutures, ear,
nose,
Soft tissues
Metals (Ti and
its alloys Co-Cr
alloys, stainless
Steels)
Strong Tough
ductile
May corrode,
dense, Difficult
to make
Joint
replacement,
Bone plates and
Screws, dental
root
Implant, pacer,
and
suture
Type of biomaterial
Materials Advantage Disadvantage Example
Ceramics
(Aluminum Oxide,
alcium phosphates,
including
hydroxyapatite
carbon)
Very
biocompatible
Inert strong in
compression
Very
biocompatible
Inert strong in
compression
Dental coating
Orthopedic
implants
Femoral head of
hip
Composites
(Carbon-carbon,
wire Or fiber
reinforced
Bone cement)
Compression
strong
Difficult to make Joint implants
Heart valves
 The science of biomedical materials involves a study
of the composition and properties of materials and
the way in which they interact with the environment
in which they are placed.
 The number of medical devices used each year is
very large. The chart below estimates usage for
common devices.
Device Usage Estimate
Contact lens 75,000,000
Hip and knee prostheses 1,000,000
Catheter 300,000,000
Heart valve 200,000
Vascular graft 400,000
Breast implant 300,000
Dental implant 500,000
Pace maker 200,000
Renal dialyzer 25,000,000
Cardiovascular 2,000,000
Intraocular lens 7,000,000
Left ventricular assist devices 100,000
Selection of Biomedical Materials
 The process of material selection should ideally be for a logical
sequence involving:
1- Analysis of the problem;
2- Consideration of requirement;
3- Consideration of available material and their properties leading to:
4- Choice of material
 The choice of a specific biomedical material is now determined by
consideration of the following:
1- A proper specification of the desired function for the material;
2- An accurate characterization of the environment in which it must
function, and the effects that environment will have on the properties of
the material;
3- A delineation of the length of time the material must function;
4- A clear understanding of what is meant by safe for human use.
Materials Evaluation
 As the number of available materials increases, it
becomes more and more important to be protected
from unsuitable products or materials, which haven't
been thoroughly evaluated.
 Most manufacturers of materials operate an
extensive quality assurance program and materials
are thoroughly tested before being released to the
general practitioner.
Materials Evaluation
 1- Standard Specifications: Many standard
specification tests of both national and international
standards organizations (ISO) are now available,
which effectively maintain quality levels. Such
specifications normally give details for:
(a) the testing of certain products,
(b) the method of calculating the results
(c) the minimum permissible result, which is
acceptable.
Materials Evaluation
 2- Laboratory Evaluation: Laboratory tests, some of
which are used in standard specification, can be used to
indicate the suitability of certain materials. It is
important that methods used to evaluate materials in
laboratory give results, which can be correlated with
clinical experience.
 3- Clinical Trials: Although laboratory tests can provide
many important and useful data on materials, the
ultimate test is the controlled clinical trial and verdict of
practitioners after a period of use in general practice.
Materials Evaluation
 results in the laboratory, only to be found lacking when
subjected to clinical use. The majority of manufacturers
carry out extensive clinical trials of new materials,
normally in cooperation with a university or hospital
department, prior to releasing a product for use by
general practitioners.
 The most common classes of materials used as
biomedical materials are polymers, metals, and
ceramics. These three classes are used singly and in
combination to form most of the implantation devices
available today.
Are transplants the solution to spare parts?
 One option for replacing diseased or damaged
body parts is to use already living tissue often in the
form of an organ, as the ‘spare part’. A heart–lung
transplant is an example.
 A ‘transplant’ is a tissue or an organ moved from
one body, or body part, to another. Coronary
bypasses using the patient’s own sapphanous veins
or spinal fusion using bone from the iliac crest are
examples.
Types Of Transplants
 Autograft: transplant of tissue or organ from one part
of a person to another location in the same person.
Autografts are often considered the in surgery.
However, there is limited availability and autografts
may deteriorate with time due to differences in their
physiological loads and the biological environment in
the transplant site.
 Homograft transplant of tissue or an organ from one
human to another. Genetic differences give rise to
rejection by the immune system and availability are the
primary factors limiting use of homografts.
Types Of Transplants
 Heterograft or Xenograft transplant of tissue or an
organ from another species to human. There are
increased genetic concerns, potentially circumvented
by genetic engineering of the animal creating a
‘transgenic species’, that limit the use of
heterografts.
 At present technical and ethical issues limit the use
of heterografts to non-living tissue replacements,
e.g. porcine heart valves and demineralised bovine
bone as a bone graft substitute.
Implants and prostheses as spare parts
 Because of limited supply, immune rejection and
other concerns regarding use of transplants, most of
the need for human spare parts is provided by
implants.
 Implants are defined as ‘A man-made material or
device inserted or embedded surgically in the
body’. Because implants are man-made and do
not contain foreign proteins, they therefore do not
elicit an immune response from the host.
The limitations of implants
 Implants are limited in function and survivability
because they are not living. Natural living tissues have
a genetically programmed capacity for self-repair.
Consequently, natural tissues can adapt to their
physiological environment.
 No man-made material is capable of self-repair or
adaptation. The interface between prosthesis and its
host tissue is especially susceptible to stress Mismatch in
either biochemical or biomechanical factors can lead to
interfacial deterioration and eventual failure.