1. 9/19/2018
Biomaterials
Lec # 1-2

2. What is a Biomaterial?
A biomaterial is a nonviable material used in a medical device, intended to interact with biological systems (Williams, 1987)
[OR]
Any material of natural or of synthetic origin that comes in contact with tissue, blood or biological fluids, and intended for use in prosthetic, diagnostic, therapeutic or storage application without adversely affecting the living organism and its components.
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3. Term Definitions
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.
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4. Fields of Knowledge to Develop Biomaterials
1- Science and engineering: (Materials Science) structure-property relationships of synthetic and biological materials including metals, ceramics, polymers, composites, tissues (blood and connective tissues), etc. 2- Biology and Physiology: Cell and molecular biology, anatomy, animal and human physiology, histopathology, experimental surgery, immunology, etc. 3- 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.
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5. 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, intra-ocular lens
Correct functional abnormalities
Cardiac pacemaker
Correct cosmetic problem
Mastectomy augmentation,
chin augmentation
Aid to diagnosis
Probes and catheters
Aid to treatment
Catheters, drains
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6. Biomaterials in Organs
Example
Heart
Cardiac pacemaker, artificial heart valve, Totally artificial heart
Lung
Oxy-generator machine
Eye
Contact lens, intraocular lens
Ear
Artificial stapes, cochlea implant
Bone
Bone plate, intra-medullary rod
Kidney
Kidney dialysis machine
Bladder
Catheter and stent
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7. Need for Biomaterials
Millions of patients suffer end stage organ and tissue failure annually.
8 million surgical procedures.
Treatment options include transplantation, reconstruction, mechanical devices.
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8. The options and Limitations
Transplantation
Critical donor shortage
3000 livers annually for people in need
Disease Transmission
HIV
Hepatitis
Other transmittable diseases.
Surgical Reconstruction
Not always possible
Complications
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9. Continues… Mechanical Devices
Engineering approach – engineer new tissues, systems
Limited by
Complexity of the human body
Multiple functions
Living components versus non living components
Materials?
Tissue based
Polymers
Metals
Ceramics
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10. Commonly Used Biomaterials
Material Applications
Silicone rubber Catheters, tubing
Dacron Vascular grafts
Cellulose Dialysis membranes
Polyurethanes Catheters, pacemaker leads
Hydrogels Ophthalmological devices, Drug Delivery
Stainless steel Orthopedic devices, stents
Titanium Orthopedic and dental devices
Alumina Orthopedic and dental devices
Hydroxyapatite Orthopedic and dental devices
Collagen (reprocessed) Ophthalmologic applications, wound dressings
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11. Significance of Biomaterials
Replace diseased part – Dialysis
Assist in Healing – Sutures
Improves Function – Contacts
Correct Function – Spinal rods
Correct Cosmetic – Nose, Ear
Aids – Probes / Catheters
Replace dead - Skin
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12. Characteristics of Biomaterials
Physical Requirements
Hard Materials.
Flexible Material.
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.
Biocompatibility is defined as the property of being biologically compatible by not producing a toxic, injurious, or immunological response in living tissue. The human body has an extraordinary ability to be able to tell whether an object is foreign or not. This is part of the bodies protection against invasion from an outside organism. If a substance is placed in the body and the body can tell it is foreign, then an immune system response will be generated. When an object is incorporated into the body without any immune responses it is said to be BIOCOMPATIBLE. In order for a device to be biocompatible, it must follow a very stringent set of demands from the body. 
The device must be very strong so it does not break inside the body. Depending on the circumstances, it may need to be either very hard or very flexible. Anything placed into the body must be able to take a constant physical beating from one's body. For instance, the valves in a heart open and close about times a minute. Over the course of years and years this adds up to millions of pumps. If the artificial valve cannot meet these standards and fails, the person will die. 
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13. History
More than 2000 years ago, Romans, Chinese, and Aztec’s used gold in dentistry.
Turn of century, synthetic implants become available.
1937 Poly(methyl methacrylate) (PMMA) introduced in dentistry.
1958, Rob suggests Dacron Fabrics can be used to fabricate an arterial prosthetic.
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14. Synthetic BIOMATERIALS
Polymers
Skin/cartilage
Drug Delivery Devices
Ocular implants
Bone replacements
Orthopedic screws/fixation
Ceramics
Metals
Heart valves
Synthetic BIOMATERIALS
Semiconductor Materials
Dental Implants
Dental Implants
Biosensors
Implantable Microelectrodes
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15. First Generation Biomaterials
Specified by physicians using common and borrowed materials.
Most successes were accidental rather than by design.
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16. Second Generation of Biomaterials
Developed through collaborations of physicians and engineers.
Engineered implants using common and borrowed materials.
Built on first generation experiences.
Used advances in materials science (from other fields).
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17. Third generation implants
Bioengineered implants using bioengineered materials.
Few examples on the market.
Some modified and new polymeric devices.
Many under development.
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18. Examples of Biomaterial Applications
Heart Valve
Artificial Tissue
Dental Implants
Intraocular Lenses
Vascular Grafts
Hip Replacements
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19. Heart Valve
Fabricated from carbons, metals, fabrics, and natural valves.
Must NOT React With Chemicals in Body.
Attached By Polyester Mesh.
Tissue Growth Facilitated By Polar Oxygen- Containing Groups.
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20. Heart Valve
Almost as soon as valve implanted cardiac function is restored to near normal.
Bileaflet tilting disk heart valve used most widely.
More than 45,000 replacement valves implanted every year in the United States.
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21. Bileaflet Heart Valves
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22. Problems with Heart Valve’s
Degeneration of Tissue.
Mechanical Failure.
Postoperative infection.
Induction of blood clots.
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23. Dental Implants
Small titanium fixture that serves as the replacement for the root portion of a missing natural tooth.
Implant is placed in the bone of the upper or lower jaw and allowed to bond with the bone.
Most dental implants are: pure titanium screw-shaped cylinders that act as roots for crowns and bridges, or as supports for dentures.
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24. Capable of bonding to bone, a phenomenon known as "osseointegration”.
Dental Implants
Capable of bonding to bone, a phenomenon known as "osseointegration”.
Bio-inert, there is no reaction in tissue and no rejection or allergic reactions.
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25. Dental Implants
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26. Intraocular Lenses Made of PMM, silicone, and other materials.
By age 75 more than 50% of population suffers from cataracts.
1.4 million implantations in the United States yearly.
Good vision is generally restored almost immediately after lens is inserted.
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27. Intraocular Lenses
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28. Hip-Replacements Most Common Medical Practice Using Biomaterials.
Corrosion Resistant high-strength Metal Alloys.
Very High Molecular Weight Polymers.
Thermoset Plastics.
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29. Hip-Replacements
Some hip replacements ambulatory function restored within days after surgery.
Others require an extensive healing period for attachment between bone and the implant.
Most cases good function restored.
After years, implant loosens requiring another operation.
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30. Hip-Replacements
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31. Biomaterials - An Emerging Industry
Next generation of medical implants and therapeutic modalities.
Interface of biotechnology and traditional engineering.
Significant industrial growth in the next 15 years -- potential of a multi-billion dollar industry.
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32. Biomaterials Companies
Baxter International develops technologies related to the blood and circulatory system.
Biocompatibles Ltd. develops commercial applications for technology in the field of biocompatibility.
Carmeda makes a biologically active surface that interacts with and supports the bodys own control mechanisms
Collagen Aesthetics Inc. bovine and human placental sourced collagens, recombinant collagens, and PEG-polymers
Endura-Tec Systems Corp. bio-mechanical endurance testing ofstents, grafts, and cardiovascular materials
Howmedica develops and manufactures products in orthopaedics.
MATECH Biomedical Technologies, development of biomaterials by chemical polymerization methods.
Medtronic, Inc. is a medical technology company specializing in implantable and invasive therapies.
Molecular Geodesics Inc., biomimetic materials for biomedical, industrial, and military applications
Polymer Technology Group is involved in the synthesis, characterization, and manufacture of new polymer products.
SurModics, offers PhotoLink(R) surface modification technology that can be used to immobilize biomolecules
W.L. Gore Medical Products Division, PTFE microstructures configured to exclude or accept tissue ingrowth.
Zimmer, design, manufacture and distribution of orthopaedic implants and related equipment and supplies
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33. Development of biomaterials devices: Fig 6.
It provides a perspective on how different disciplines work together,
starting from the identification of a need for a biomaterial through
development,
manufacture,
implantation, and
removal from the patient.
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35. Success and Failure
Most biomaterials and medical devices perform satisfactorily, improving the quality of life for the recipient or saving lives.
However, no manmade construct is perfect.
All manufactured devices have a failure rate.
Also, all humans are different with differing genetics, gender, body chemistries, living environment, and degrees of physical activity.
Furthermore, physicians implant or use these devices with varying degrees of skill.
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36. Success and Failure
The other side to the medical device success story is that there are problems, compromises, and complications that occur with medical devices.
Central issues for the biomaterials scientist, manufacturer, patient, physician, and attorney are,
(1) what represents good design,
(2) who should be responsible when devices perform " with an inappropriate host response," and
(3) what are the cost/risk or cost/benefit ratios for the implant or therapy?
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37. THANKS
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