BIOMATERIALSENT 311/4

Course overview

Prepared by: Nur Farahiyah Binti Mohammad

Date: 7th July 2008

Email : farahiyah@unimap.edu.my

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Course structure

Course code: ENT 311/4 Lecturer: Miss Nur Farahiyah Mohammad Mr Nashrul Fazli Mohd Nasir Teaching Engineer: Miss Adilah Hashim Course synopsis Course outcome 12 topics Lesson plan

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Course assessment

Final Exam : 50% Test/Quiz : 10% Lab assessment : 30% Assignment : 10% 100%

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List of text book and references

Text book:1. Buddy D. Ratner, Allan S. Hoffman, Frederick J. Schoen & Jack E.

Lemons. Biomaterials Science: An Introduction to Materials in Medicine. 2nd Ed., Elsevier Academic Press, 2004.

2. Johnna S. Temenoff and Antonios G. Mikos. Biomaterials: The Intersection of Biology and Materials Science. Prentice Hall, 2008.

Reference book:1. Joon B. Park & Joseph D. Bronzino. Biomaterials: Principles and

Applications, CRC Press, 2002. 2. Joyce Y. Wong & Joseph D. Bronzino. Biomaterials, CRC Press, 2007.3. Joon B. Park & Roderic S. Lakes. Biomaterials: An Introduction, 2nd

Ed., Plenum Press, 1992.4. Sujata V. Bhat. Biomaterials, 2nd Ed., Alpha Science International

Ltd, 2005.5. Donglu Shi. Biomaterials and tissue engineering, Springer, 2004.

Lecture 1: Introduction to Biomaterials

BIOMATERIALSENT 311/4

Prepared by: Nur Farahiyah Binti Mohammad

Date: 7th July 2008

Email : farahiyah@unimap.edu.my

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Objective

Define biomaterials Describe biomaterial applications Define and describe biocompatibility

principle Explain factors contribute to the

performance of biomaterials in the body.

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What is it biomaterial?

A material intended to interface with biological systems to evaluate, treat, augment, or replace any tissue, organ or function of the body (Williams, 1999).

Any substance (other than drugs) or combination of substance , synthetic or natural origin, which can be used for any period of time, as a whole or as a part of a system which treats, augments, or replace any tissue, organ or function of the body (Williams, 1987).

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A biomaterial is any material, natural or man-made, that comprises whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function" (Wikipedia).

“A systemically and pharmacologically inert substance designed for implantation within or incorporation with living system” (The

Clemson University advisory Board for Biomaterials).

What is it biomaterial?

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Biomaterial Application in Human Body

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Biomaterials history

Year Development

Late 18th–19th century

1860-1870

Early 1900

Various metal device to fix bone fracture: wire and pins from Fe(Iron), Au (gold), Ag(silver), Pt (platinum)

Aseptic surgical units(The use of biomaterials did not become practical until the advent of an aseptic surgical technique develop by Dr J. Lister.)

Bone plates were introduced to aid in fixation of long bone fracture. However, many of these early plates broke due unsophisticated mechanical design; -too thin -Had stress concentrating corners. -Corrode rapidly in the bodyIntroduction of stainless steel and cobalt chromium alloys

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Biomaterials history

Year Development

1930s

1938

1940s

1946

1950s

1960s

Introduction of stainless steel and cobalt chromium alloys

First total hip replacement prosthesis.

First used polymethyl methacrylate (PMMA) for corneal implant and replacement of section of damaged skull bone. (During World War II shattered perspex in pilots didn’t cause problem.)

First biomechanically designed femoral head replacement prosthesis: first plastic (PMMA) used in joint replacement.

First successful blood vessel replacement

First commercial heart valve replacementCemented joint replacement

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Current status of the field

Today, biomaterials represent a significant portion of the healthcare industry, with an estimated market size of over $9 billion per year in the United States.

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Cardiovascular area: approximately 100,00

replacement heart valves and 300,000 vascular graft implanted per year in US.

Artificial joints replacements: Over 500,000 artificial joint

replacements, such as knee or hip, are implanted yearly in United States.

Current status of the field

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Future Directions

Starting 1960s-1970s The first generation of biomaterials was

designed to be inert, or not reactive with the body

Decreasing the potential for negative immune response to the implant.

In 1990’s until now Materials designed to be bioactive,

interacting in positive manner with the body to promote localized healing.

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Development of “smart” material which can help guide the biological response in the implant area.

Design of injectable materials that can applied locally and with minimal pain to the patient.

New set of nano-structured biomaterials for nano-scale objects as reinforcing agents.

Future Directions

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Application of Biomaterials

Biomaterials that will be used may be considered from the point of view of the problem area that is to be solved:

Problem Area Examples

Replacement of diseased or damaged part

Assist in healing

Improve function

Correct functional abnormality

Correct cosmetic problem

Aids to diagnosis

Aid to treatment

Artificial hip joint, kidney dialysis machine

Sutures, bone plates, and screws

Cardiac pacemaker, intraocular lens, cochlear implant

Cardiac pacemaker

Breast implant, soft tissue augmentation, chin augmentation

Probes, catheter

Catheters, drains

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Application of Biomaterials

Biomaterials that will be used may be considered from the point of view of the organ that will need to be replaced or improve:

Organ Heart

Heart

LungEyeEarBoneKidneyBladder

Cardiac pacemaker, artificial heart valve, total artificial heartOxygenator machineContact lens, intraocular lensCochlear implantBone plate, screwKidney dialysis machineCatheter and stent

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Biomaterials are classified as: Organic if contain carbon Inorganic if they do not.

More specifically biomaterials fall into one of three of materials: Metals (inorganic material) Ceramics(inorganic material) Polymers (organic material)

Type of Biomaterials

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Type of Biomaterials

Biomaterials

Inorganic Organic

Metals Ceramics Polymers

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Type of Biomaterials

Materials Advantages Disadvantages Examples

PolymersNylon,Polyethylene,Silicone, Teflon,Dacron,Acrylates,PGA, PLA

Resilient,Easy to fabricate

Not Strong, Deforms with time, may degrade

Sutures, vascular graft, hip socket, intraocular lenses

Metals(Titanium and its alloys, Co-Cr alloys, stainless steel,Gold)

Strong, Tough,Ductile

May corrode,Dense,Difficult to make

Joint replacement,Bone plates and screws, Dental root implant

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Type of Biomaterials

Materials Advantages Disadvantages Examples

CeramicsAluminum oxide, Calcium phosphates,Carbon

Very biocompatible,Inert,Strong in compression

Brittle,Not resilient, Difficult to make

Dental implant, Femoral head of hip replacement,Coating of dental and orthopedic implants

CompositesCarbon-carbonCeramic-polymer

Strong, less stiff than metals,Strong in compression

Difficult to make,Weak in tension

Joint implantsDental fillings

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Performance of biomaterials

The success of biomaterials in the body depends on factors such as: Material properties Design of the implants Biocompatibility of the materials Technique used by the surgeon Health and condition of the patient Patient activities

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The Concept of Biocompatibility

Definition of biocompatibility:

“Biocompatibility is the ability of a material to perform with an appropriate host response in a specific application” (William, 1987).

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The Concept of Biocompatibility

Biocompatibility characteristic: Biocompatibility involves the acceptance

of an artificial implant by the surrounding tissues and by the body as a whole.

Biocompatible materials Do not irritate the surrounding structures Do not provoke an abnormal inflammatory

response Do not incite allergic or immunologic reactions Do not cause cancer

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The Concept of Biocompatibility

Biocompatible materials have adequate mechanical properties.

Biocompatible materials have appropriate optical properties (eye).

Biocompatible materials have appropriate density.

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The End

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Supplementary slide

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Course synopsis

This course is designed to provide a basic knowledge of biomaterials and to provide understanding of interactions between physiological components and biomaterials.

Ranges of materials currently being utilized for various biomedical applications and their biocompatibility with references to the biological responses and environments available will be discussed.

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Course Outcomes

CO1:Ability to describe the concept of biocompatibility and basic concepts of materials used in medical application.

CO2: Ability to explain and evaluate the biocompatibility of biomaterials utilized as implants or contact devices with human tissues.

CO3:Ability to explain and illustrate tissue reactions to biomaterials.

CO4:Ability to select biomaterials that can be used for different medical applications and explain the criteria that will lead to a successful implants.

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Examples of Biomaterials application

Artificial hip joint Needed because natural joint

wear out. Replacement hip joint are

implanted in more than 90 000 humans each year in US.

Fabricated from titanium, ceramics, composite, UHMWPE.

After 10-15 years, the implant may loose, require another operation.

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Examples of Biomaterials application

Prosthetic Heart valve

Fabricated from carbon, metal, elastomers, fabrics, natural valves and tissue chemically pre-treated.

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Show good performance as soon as the valve is implanted but have some problems: Degeneration of tissue Mechanical failure Postoperative infection Induction of blood cloth

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Examples of Biomaterials application

Intraocular lenses (IOL) Used to replace a natural lense

when it become cloudy due to cataract formation.

Fabricated of poly (methyl methacrylate), silicone elastomer, soft acrylic polymers or hydrogels.

Complication: IOL stimulate outgrowth cells from the posterior lens capsule → cloud the vision.

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Week Content / Lecture Topic

Week 1 Introduction to Biomaterials

Week 2 Properties of biomaterials

Week 3 Polymeric Biomaterials

Week 4 Metallic Biomaterials

Week 5 Ceramic Biomaterials

Week 6 Tissue Reaction to Biomaterials

Week 7 Semester Break

Week 8 Tissue Reaction to BiomaterialsMid Semester Test

Week 9 Biological Testing of Biomaterials

Week 10 Blood Contacting Implant

Week 11 Non-blood Interfacing Implant

Week 12 Hard Tissue Replacement: Internal Fixation and Joint Replacement

Week 13 Special Break

Week 14 Hard Tissue Replacement: Internal Fixation and Joint Replacement

Week 15 Tissue Engineering

Week 16 Scaffolds for Tissue EngineeringAssignment Presentation

Week 17 Revision week

Week 18-20 Final Examination