06/26/14 1Suganthan / Biomaterials
 To introduce the different biomaterials
used in Biomedical Engineering.
 To provide some fundamentals properties
of the...
 Historically, biomaterials consisted of materials
common in the laboratories of physicians, with little
consideration of...
 1860’s – Lister develops aseptic surgical technique
 Early 1900’s: Bone plates used to fix fractures.
 1930’s: Introdu...
 A biomaterial is a nonviable material used in a medical
device, intended to interact with biological systems
(Williams, ...
 Millions of patients suffer end stage organ
and tissue failure annually.
 $400 billion annually for treatment.
 8 mill...
 Transplantation
 Critical donor shortage
▪ 3000 livers annually for 30000 people in need
 Disease Transmission
▪ HIV
▪...
 Mechanical Devices
 Engineering approach – engineer new tissues,
systems
 Limited by
▪ Complexity of the human body
▪ ...
Material Applications
 Silicone rubber Catheters, tubing
 Dacron Vascular grafts
 Cellulose Dialysis membranes
 PMMA I...
 Replace diseased part – Dialysis
 Assist in Healing – Sutures
 Improves Function – Contacts
 Correct Function – Spina...
 ‘Ad-hoc’ [unplanned] Implants
 Specified by physicians using common and borrowed
materials
 Most successes were accide...
3 basic materials – PMMA, Acrylic, silicone
06/26/14 12Suganthan / Biomaterials
06/26/14 13Suganthan / Biomaterials
 Engineered implants using common and borrowed materials
 Developed through collaborations of physicians and engineers
...
06/26/14 15Suganthan / Biomaterials
 Bioengineered implants using bioengineered materials
 Few examples on the market
 Some modified and new polymeric devi...
06/26/14 17Suganthan / Biomaterials
…In the shape of a nose [left] is seeded with cells called
chondrocytes that replace the polymer with cartilage over
time ...
Structural
Soft Tissue
Replacements
Functional Tissue
Engineering
Constructs
++
++
06/26/14 19Suganthan / Biomaterials
 Cell matrices for 3-D growth and tissue
reconstruction
 Biosensors, Bio-mimetic and Smart devices
 Controlled Drug Del...
Synthetic
Biomaterials
Semiconductor
Materials
CeramicsMetals
Polymers
Dental Implants
Bone replacements
Dental Implants
H...
 Bioresorbable Vascular Graft
 Biodegradable nerve guidance channel
 Skin Grafts
 Bone Replacements
06/26/14 22Suganth...
 Next generation of medical implants and therapeutic
modalities
 Interface of biotechnology and traditional engineering
...
06/26/14 24Suganthan / Biomaterials
Orthopedics
Examples of biomaterials
used in orthopaedic
applications include:
• Joint replacements (hip,
knee)
• Bone cem...
Examples of biomaterials
used in dental
applications include:
• Pins for anchoring tooth
implants and also part of
orthodo...
Biomaterials are widely used in
cardiovascular equipment and
devices to be inserted into
biological systems.
Examples incl...
Examples of biomaterials
used in ophthalmic
applications include:
• Contact lenses
• Corneal implants
• Artificial corneas...
06/26/14 29Suganthan / Biomaterials
Examples of biomaterials
used in cosmetic
applications include:
• Silicones for breast
enlargement.
• Artificial skin
06/2...
 Storage of fluids, tissues and other biological
products.
 Diagnosis
 Monitoring
 Therapy
06/26/14 31Suganthan / Biom...
A medical device is a product which is
used for medical purposes in patients, in
diagnosis, therapy or surgery
06/26/14 32...
Based on the duration of the device use,
invasiveness and risk to the user.
06/26/14 33Suganthan / Biomaterials
CLASS I devices: crutches, bedpans, tongue depressors,
adhesive bandages etc. – minimal invasiveness, does not
contact the...
 Although FDA recognizes that many of the currently
available biomaterials have vast utility in the
fabrication of medica...
 Accurate characterization is an essential step in
selecting a material for a medical device, but
ultimately the final as...
 It is dominated as much
 By the regulatory approval process and
 Submission requirements as by the
▪ Physical
▪ Mechan...
Biomaterials include
 Physical scientists,
 Engineers,
 Dentists,
 Biological scientists,
 Surgeons, and
 Veterinary...
Study the interactions of natural and
synthetic substances and implanted
devices
With living cells, their components and...
Develop and characterize the materials
used to measure, restore and improve
physiologic function, and enhance
survival an...
A professional society which promoted advances in all
phases of materials research and development by
encouragement of co-...
 Journal of Biomedical Materials Research
 Biomaterials
 Journal of Biomaterials Science
 Journal of Biomaterials Appl...
 Biocompatibility is related to the behavior of
biomaterials in various environments under various
chemical and physical ...
 The ambiguity of the term reflects the ongoing
development of insights into how biomaterials
interact with the human bod...
 The ability of a material to perform with an appropriate host
response in a specific application (Williams, 1987). OR
 ...
 Refers to the ability of a biomaterial to perform its desired
function with respect to a medical therapy, without elicit...
Bulk Properties
Surface Properties
Characterization
06/26/14 47Suganthan / Biomaterials
 The bulk elastic properties of a material
determine how much it will compress under
a given amount of external pressure....
 These are the most important property that a
biomaterial possesses.
 This is due to the fact that, when a device is
imp...
 Polymeric materials doesn’t corrode, but leach the
constituents such as lubricants, monomers from
their interiors.
 Ino...
a. Thermal treatment.
b. Surface Improvement.
c. Sterilization.
06/26/14 51Suganthan / Biomaterials
a. The toughness of a biomaterial can be increased by
this treatment below the melting temperature of
the material, for a ...
 Ammonization is one of its method. It means an oxide film
formation on the metal.
 Nitrating is another method.
 Gener...
 The surgical implants must be freed from microorganisms by
post manufacturing sterilization.
 This will destroy most of...
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Biomaterials – an overview

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Biomaterials – an overview

  1. 1. 06/26/14 1Suganthan / Biomaterials
  2. 2.  To introduce the different biomaterials used in Biomedical Engineering.  To provide some fundamentals properties of these materials,  And indicate how they are used. 06/26/14 2Suganthan / Biomaterials
  3. 3.  Historically, biomaterials consisted of materials common in the laboratories of physicians, with little consideration of materials properties.  Early biomaterials:  Gold: Malleable, inert metal [does not oxidiize], used in dentistry.  Iron, Brass: High Strength Metals, rejoin fractured femur  Glass: Hard ceramic, used to replace eye [cosmetic]  Wood: Natural composite, high strength to weight, used for limb prostheses.  Bone: Natural composite. 06/26/14 3Suganthan / Biomaterials
  4. 4.  1860’s – Lister develops aseptic surgical technique  Early 1900’s: Bone plates used to fix fractures.  1930’s: Introduction of S.S, cobalt chromium alloys.  1938: First total hip prosthesis  1940’s: Polymers in medicine: PMMA bone repair, cellulose for dialysis, nylon sutures.  1952: Mechanical heart valve  1953: Dacron [polymer fiber] vascular grafts  1958: Cemented [PMMA] joint replacement  1960: first commercial heart valve  1970’s: PEO protein resistant thin film coating  1976: FDA amendment governing testing & production of biomaterials / devices  1976: Artificial heart06/26/14 4Suganthan / Biomaterials
  5. 5.  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. 06/26/14 5Suganthan / Biomaterials
  6. 6.  Millions of patients suffer end stage organ and tissue failure annually.  $400 billion annually for treatment.  8 million surgical procedures.  Treatment options include transplantation, reconstruction, mechanical devices. 06/26/14 6Suganthan / Biomaterials
  7. 7.  Transplantation  Critical donor shortage ▪ 3000 livers annually for 30000 people in need  Disease Transmission ▪ HIV ▪ Hepatitis ▪ Other transmittable diseases.  Surgical Reconstruction  Not always possible  Complications 06/26/14 7Suganthan / Biomaterials
  8. 8.  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 06/26/14 8Suganthan / Biomaterials
  9. 9. Material Applications  Silicone rubber Catheters, tubing  Dacron Vascular grafts  Cellulose Dialysis membranes  PMMA Intraocular lenses, bone cement  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 06/26/14 9Suganthan / Biomaterials
  10. 10.  Replace diseased part – Dialysis  Assist in Healing – Sutures  Improves Function – Contacts  Correct Function – Spinal rods  Correct Cosmetic – Nose, Ear  Aids – Probes / Catheters  Replace rotten – Amalgam  Replace dead - Skin 06/26/14 10Suganthan / Biomaterials
  11. 11.  ‘Ad-hoc’ [unplanned] Implants  Specified by physicians using common and borrowed materials  Most successes were accidental rather than by design Examples – First generation Implants  Gold fillings, wooden teeth, PMMA dental prosthesis  Steel, gold, ivory, bone plates etc.  Glass eyes and other body parts 06/26/14 11Suganthan / Biomaterials
  12. 12. 3 basic materials – PMMA, Acrylic, silicone 06/26/14 12Suganthan / Biomaterials
  13. 13. 06/26/14 13Suganthan / Biomaterials
  14. 14.  Engineered implants using common and borrowed materials  Developed through collaborations of physicians and engineers  Built on first generation experiences  Used advances in materials science Examples – Second generation implants  Titanium alloy dental and orthopedic implants  Cobalt-chromium implants  UHMW polyethylene bearing surfaces for total joint replacements  Heart valves and Pacemakers. 06/26/14 14Suganthan / Biomaterials
  15. 15. 06/26/14 15Suganthan / Biomaterials
  16. 16.  Bioengineered implants using bioengineered materials  Few examples on the market  Some modified and new polymeric devices  Many under development Example – Third generation implants  Tissue engineered implants designed to re-grow rather than replace tissues  Some resorbable bone repair cements  Genetically engineered ‘biological’ components. 06/26/14 16Suganthan / Biomaterials
  17. 17. 06/26/14 17Suganthan / Biomaterials
  18. 18. …In the shape of a nose [left] is seeded with cells called chondrocytes that replace the polymer with cartilage over time [right] to make a suitable implants. 06/26/14 18Suganthan / Biomaterials
  19. 19. Structural Soft Tissue Replacements Functional Tissue Engineering Constructs ++ ++ 06/26/14 19Suganthan / Biomaterials
  20. 20.  Cell matrices for 3-D growth and tissue reconstruction  Biosensors, Bio-mimetic and Smart devices  Controlled Drug Delivery / Targeted Delivery  Bio-hybrid organs and Cell Immuno-isolation  New biomaterials – bioactive, biodegradable, inorganic  New processing techniques 06/26/14 20Suganthan / Biomaterials
  21. 21. Synthetic Biomaterials Semiconductor Materials CeramicsMetals Polymers Dental Implants Bone replacements Dental Implants HeartValves Orthopedic Screws Biosensors Implantable Microelectrodes Drug delivery Devices Ocular Implants 06/26/14 21Suganthan / Biomaterials
  22. 22.  Bioresorbable Vascular Graft  Biodegradable nerve guidance channel  Skin Grafts  Bone Replacements 06/26/14 22Suganthan / Biomaterials
  23. 23.  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. 06/26/14 23Suganthan / Biomaterials
  24. 24. 06/26/14 24Suganthan / Biomaterials
  25. 25. Orthopedics Examples of biomaterials used in orthopaedic applications include: • Joint replacements (hip, knee) • Bone cements • Bone defect fillers • Fracture fixation plates • Artificial tendons and ligaments. 06/26/14 25Suganthan / Biomaterials
  26. 26. Examples of biomaterials used in dental applications include: • Pins for anchoring tooth implants and also part of orthodontic devices. • Dentures made from polymeric biomaterials. 06/26/14 26Suganthan / Biomaterials
  27. 27. Biomaterials are widely used in cardiovascular equipment and devices to be inserted into biological systems. Examples include: • Carbon used in heart valves • Polyurethane for pace makers. Their use depends on the specific application and the design.06/26/14 27Suganthan / Biomaterials
  28. 28. Examples of biomaterials used in ophthalmic applications include: • Contact lenses • Corneal implants • Artificial corneas • Intraocular lenses 06/26/14 28Suganthan / Biomaterials
  29. 29. 06/26/14 29Suganthan / Biomaterials
  30. 30. Examples of biomaterials used in cosmetic applications include: • Silicones for breast enlargement. • Artificial skin 06/26/14 30Suganthan / Biomaterials
  31. 31.  Storage of fluids, tissues and other biological products.  Diagnosis  Monitoring  Therapy 06/26/14 31Suganthan / Biomaterials
  32. 32. A medical device is a product which is used for medical purposes in patients, in diagnosis, therapy or surgery 06/26/14 32Suganthan / Biomaterials
  33. 33. Based on the duration of the device use, invasiveness and risk to the user. 06/26/14 33Suganthan / Biomaterials
  34. 34. CLASS I devices: crutches, bedpans, tongue depressors, adhesive bandages etc. – minimal invasiveness, does not contact the user internally. CLASS II devices: Hearing aids, blood pumps, catheters, contact lens, electrodes etc. – higher degree of invasiveness and risk, but relatively short duration. CLASS III devices: Cardiac pacemakers, intrauterine devices, intraocular lenses, heart valves, orthopedic implants etc. – considerably more invasive and can immense risk to the user-implantables. 06/26/14 34Suganthan / Biomaterials
  35. 35.  Although FDA recognizes that many of the currently available biomaterials have vast utility in the fabrication of medical devices, the properties and safely of these materials must be carefully assessed with respect to the specific application in question and its degree of patient contact.  An important principle in the safety assessment of medical devices is that a material that was found to be safe for one intended use in a device might not be safe in a device intended for a different use 06/26/14 35Suganthan / Biomaterials
  36. 36.  Accurate characterization is an essential step in selecting a material for a medical device, but ultimately the final assessment must be performed on the finished product, under actual use conditions. 06/26/14 36Suganthan / Biomaterials
  37. 37.  It is dominated as much  By the regulatory approval process and  Submission requirements as by the ▪ Physical ▪ Mechanical and ▪ Chemical properties of the medical device. 06/26/14 37Suganthan / Biomaterials
  38. 38. Biomaterials include  Physical scientists,  Engineers,  Dentists,  Biological scientists,  Surgeons, and  Veterinary practitioners in industry- government,  Clinical specialties and academic settings. 06/26/14 38Suganthan / Biomaterials
  39. 39. Study the interactions of natural and synthetic substances and implanted devices With living cells, their components and complexes such as tissues and organs. 06/26/14 39Suganthan / Biomaterials
  40. 40. Develop and characterize the materials used to measure, restore and improve physiologic function, and enhance survival and quality of life. 06/26/14 40Suganthan / Biomaterials
  41. 41. A professional society which promoted advances in all phases of materials research and development by encouragement of co-operative educational programs, clinical applications, and professional standards in the biomaterials field. www.biomaterials.org 06/26/14 41Suganthan / Biomaterials
  42. 42.  Journal of Biomedical Materials Research  Biomaterials  Journal of Biomaterials Science  Journal of Biomaterials Applications  Journal of Material Science: Materials in Medicine 06/26/14 42Suganthan / Biomaterials
  43. 43.  Biocompatibility is related to the behavior of biomaterials in various environments under various chemical and physical conditions.  The term may refer to specific properties of a material without specifying where or how the material is to be used.  For example, a material may elicit little or no immune response in a given organism, and may or may not integrate with a particular cell type or tissue. 06/26/14 43Suganthan / Biomaterials
  44. 44.  The ambiguity of the term reflects the ongoing development of insights into how biomaterials interact with the human body and eventually how those interactions determine the clinical success of a medical device.  A material should not be toxic unless specifically engineered to be so-like ‘smart’ drug delivery systems that target cancer cells and destroy them. 06/26/14 44Suganthan / Biomaterials
  45. 45.  The ability of a material to perform with an appropriate host response in a specific application (Williams, 1987). OR  The quality of not having toxic or injurious effects on biological systems. OR  Comparison of the tissue response produced through the close association of the implanted candidate materials to its implant site within the host animal to that tissue response recognized and established as suitable with control materials. OR 06/26/14 45Suganthan / Biomaterials
  46. 46.  Refers to the ability of a biomaterial to perform its desired function with respect to a medical therapy, without eliciting any undesirable local or systemic effects in the recipient or beneficiary of that therapy, but generating the most appropriate beneficial cellular or tissue response in that specific situation, and optimizing the clinically relevant performance of that therapy. OR  Biocompatibility is the capability of a prosthesis implanted in the body to exist in harmony with tissue without causing deleterious changes. 06/26/14 46Suganthan / Biomaterials
  47. 47. Bulk Properties Surface Properties Characterization 06/26/14 47Suganthan / Biomaterials
  48. 48.  The bulk elastic properties of a material determine how much it will compress under a given amount of external pressure.  The ratio of the change in pressure to the fractional volume compression is called the bulk modulus of the material. Bulk Modulus B = ∆P ∆V / V 06/26/14 48Suganthan / Biomaterials
  49. 49.  These are the most important property that a biomaterial possesses.  This is due to the fact that, when a device is implanted to tissues, the surface chemistry will be determined, how the material [or] the surrounding fluid interact.  The surface of metal implant corrode inside the system liberating the metallic ions into the solution. 06/26/14 49Suganthan / Biomaterials
  50. 50.  Polymeric materials doesn’t corrode, but leach the constituents such as lubricants, monomers from their interiors.  Inorganic glasses and clay’s undergoes a process of ion – exchange.  Thus, proper surface properties are important to have desirable biocompatibility of implant materials. 06/26/14 50Suganthan / Biomaterials
  51. 51. a. Thermal treatment. b. Surface Improvement. c. Sterilization. 06/26/14 51Suganthan / Biomaterials
  52. 52. a. The toughness of a biomaterial can be increased by this treatment below the melting temperature of the material, for a predetermined period, of time and this process should be followed by controlled cooling. This is called Annealing. b. The other method is that, the heat treatment step is completed, the alloy is rapidly cooled. This is called quenching. 06/26/14 52Suganthan / Biomaterials
  53. 53.  Ammonization is one of its method. It means an oxide film formation on the metal.  Nitrating is another method.  Generally, oxygen or nitrogen alloys on Aluminum or Titanium base alloys are done by placing them in an electrolytic bath and passing electric current.  Grinding is another process, that results in surface layer which is used to remove surface impurities.  Polishing is used to polish the surface of the metal. 06/26/14 53Suganthan / Biomaterials
  54. 54.  The surgical implants must be freed from microorganisms by post manufacturing sterilization.  This will destroy most of the bacteria. Dry Sterilization.  The pathogens are killed by heating at 160º – 190ºC.  This should be followed by moist heat sterilization and is performed in autoclaves.  Generally a 15mins exposure at 120ºC with steam at a pressure of 0.1 atmosphere is the most common treatment. 06/26/14 54Suganthan / Biomaterials

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