biomateriais #02 - introduction

Biomateriais

MIEB/MEMAT

2011/2012

BiomaterialsBiomaterials

Class #02 – Biomaterials, Introduction

Jorge F J Coelho

Departamento de Engenharia Química

Faculdade de Ciências e Tecnologia

Universidade de Coimbra

Definition

History

Classification

Applications

SummarySummary

“… 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”

“… is a nonviable material used in medical device, intended to interact with a biological systems”

“… is a synthetic or natural material used to replace part of a living

system or to function in intimate contact with living tissue”

DefinitionDefinition

“A biomaterial can bedefined as any materialused to make devices toreplace a part or afunction of the body in asafe, reliable, economic,and physiologicallyacceptable manner.”

Park Joon, Lakes R.S., “Biomaterials – An Introduction”, 3rd edition, Springer;


“… is a systematically and pharmacologically inert substance designed for

implantation within or incorporation with living systems”

“… constitute part of medical implants, extracorporeal devices, and

disposables that have been utilized in medicine, surgery, dentistry, and

veterinary medicine as well as in every aspect of patient health care”

“… is any substance (other than a drug) or combination of substances,

synthetic or natural in origin, which can be used for any period of time, as a

whole or as a part of a system which treats, augments, or replaces any

tissue, organ, or function of the body”


WHAT??????

There is no definition universally accepted of biomaterial!

We will address in our lectures biomaterials as materials (syntheticand natural) that are used in contact with biological systems


Dental Implants in Early Civilizations

Mayan PeopleNacre teeth from sea shells

600 A.D.

RomansIron and gold teeth

200 A.D.

HistoryHistory

Linen Sutures

600 A.D.

Greeks Gold wire sutures

200 A.D.

1816

Philip Physick Lead wire sutures 1849

J. Marion SimsSilver wire sutures

HistoryHistory

Sutures

Egyptians

Contact lenses concept

1508

Leonardo DaVinci

Glass contact lens

1860

Adolf Fick

HistoryHistory

Contact Lenses

20th Century – Materials Revolution

Bone plates used to fix fractures

Introduction of stainless steel and cobalt chromium alloys

1930’s

1938 First total hip prosthesis (P. Wiles)

Most implants prior to 1939 had a low probability of success because of poor understanding of biocompatibility and sterilization

HistoryHistory

Early 1900’s

Polymers in medicine: PMMA bone repair; cellulose for dialysis; nylon sutures

PET (polymer fiber) vascular grafts1953

1960 First commercial heart valves

1940’s

1952 Mechanical heart valve

1958 Cemented* (PMMA) joint replacement

1970’s PEO** (polyethyleneoxide) protein resistant thin film coating

1976 Artificial heart (W. Kolff, Prof. Emeritus)

HistoryHistory

“Cleaned up” commodity materials used extensively

“A biomaterial is a nonviable material used in a medical device, intended to interact with biological systems”

1980

1987 Definition of a biomaterial (Williams)

1994 The word “nonviable” is removed from the definition of a biomaterial

Lycra, Teflon, Polyethene, GoreTex, Silastic, Dacron

HistoryHistory

“A biomaterial is a material used in a medical device, intended to interact with biological systems”

After 1980 – Tissue Engineering Revolution

Yannas et al. Artificial skin from collagen and glycosaminoglycan

Langer and Vacanti1993

Definition of “Tissue Engineering”

Metallic tantalum foam bone scaffold

Tissue engineered skin

HistoryHistory

1980

HistoryHistory

Biomaterials Today

Protein adsorption

Biospecific biomaterials

Nonfouling materials

Healing and the foreign body reaction

HistoryHistory

Biomaterials Today

Controlled release

Tissue engineering

Regenerative medicine

Biomimetics

“Nanobiotechnology”

HistoryHistory

Biomimetics is the process of understanding and applying biological principles to

human designs. When scientists make a machine that mimics what an organism does

Biomaterials - ClassificationBiomaterials - Classification

Polymers

Polyethylene

HydrogelsCellulose

Natural Polymers

Silicones

Synthetic Polymers

Poly(vinyl chloride)

Teflon

NylonNatural Altered

Polymers

Polymers

Biomaterials - ClassificationBiomaterials - Classification

Biomaterials -PolymersBiomaterials -Polymers

Nylon , Silicone , Rubber , Polyester , Polytetrafluoroethylene


AdvantagesResilient; easy to fabricate; high elasticity; low density; price

DisadvantagesNot strong; low mechanical strain; deforms with time; may degrade

ExamplesSutures, blood vessels, other soft tissues, hip socket, tissue engineering


Ceramics

Glasses

Carbon

Ceramic-Glasses

Bioglass

CalciumPhosphates

Silicates

Hydroxyapatite

Alumina

Zirconia Titania

http://en.wikipedia.org/wiki/Bioactive_glasshttp://www.azom.com/Details.asp?ArticleID=3625

Biomaterials -CeramicsBiomaterials -Ceramics

Alumina Zirconia , Calcium Phosphates Including Hydroxyapatite , Carbon


AdvantagesGood compatibility; corrosion resistance; inert

DisadvantagesBrittle; not resilient; week in tension; difficult to manufacture; high density; price

ExamplesDental and orthopedic implants, neuroestimulation

Ceramics


Metals

Stainless Steels

Cobalt-Based Alloys

Titanium-Based Alloys

Gold

Silver

Platinum

Biomaterials - MetalsBiomaterials - Metals

Ti and its alloys , Co-Cr alloys , Au , Ag Stainless Steels


AdvantagesHigh tension force; high use resistance; strong; tough ductile;

DisadvantagesCorrosion in physiological medium; high density; low biocompatibility, difficult to make; price

ExamplesJoint replacements, dental root implants, pacer and suture wires, bone plates and screws

Metals


Composites

PE / HA particles

Hydrogels/PET fibers

Particle-Reinforced

Fiber-Reinforced

• Composites are engineered materials made from two or more constituent materials withsignificantly different physical or chemical properties and which remain separate and distinct on amacroscopic level within the finished structure.

Biomaterials - CompositesBiomaterials - Composites

Composites


AdvantagesGood compatibility; corrosion resistance; inert material; strong; tailor-made

DisadvantagesDifficult to manufacture; price

ExamplesBone cement, dental resin, artificial valves

Composites


Mechanical, Chemical, Physical

and Surface Properties

Capacity to be… machinable,

moldable, extrudable, etc…

Non-carcinogenic, non-pyrogenic,

nontoxic, non-allergenic, blood

compatible, non-inflammatory, non

degradable (only if that is pretended)

Not destroyed or changed by

typical sterilizing techniques such

as autoclaving, dry heat,

radiation, ethylene oxide

Biomaterials Biomaterials

Right density

Biocompatible

Sterilizable

Right mechanical strength

Chemically inert and stable

Non toxic and no carcinogenic

To be used as a biomaterial

Biomaterials - Features Biomaterials - Features

The material must not leach or release soluble componentsinto the living system, unless that release is intentional

The living systems must not degrade the implant, unless thisdegradation is intentional

Relatively inexpensive, reproducible and easy to fabricateand process on a large scale

To be used as a biomaterial


Chemical analysis

Physical analysis

Biocompatibility analysis

“in vivo” tests

“in vitro” tests

Surface characterization

Biomaterials – Main Characterizations Biomaterials – Main Characterizations

Cancer

Thrombosis

Destruction of enzymes

Toxic or allergic reactions

Adverse immune responses

Damage to adjacent tissues

Alteration of plasma proteins

should carry out the task for which was thought and must NOT cause

Ideal Biomaterial Ideal Biomaterial

Biomaterials – Applications Biomaterials – Applications

The need for biomaterials stems from inability to treat many diseases,

injuries and conditions with other therapies or procedures:

Replacement of body part that lost function (total hip, heart)


Correct abnormalities (spinal rod)


Assist in healing (sutures, drug release)


Improve function (intraocular lenses)


It usually consists of a plastic

lens with plastic side struts,

called haptics, to hold the lens

in place within the capsular bag.


Intraocular lenses usually replace the

existing crystalline lens because it has

been clouded over by a cataract, or as a

form of refractive surgery to change the

eye’s optical power.

There are foldable intraocular lenses made of acrylic or silicone (simple

surgery) or inflexible lenses (typically made of PMMA) that require a

larger incision.

Major complication:

Capsule opacification caused by proliferation and migration of

residual lens epithelial cells into the visual axis


Intraocular lenses


Intraocular lenses

The lens is a transparent, biconvex structure in the eye that, along with the cornea,

helps to refract light to be focused on the retina.

Cataract is a clouding that develops in the crystalline

lens of the eye or in its envelope, varying in degree

from slight to complete opacity and obstructing the

passage of light.


Intraocular lenses

Improve function (pacemaker, stent)


A stent is either an expandable wire form or perforated tube that is

inserted into an artery, blood vessel, or other duct to hold the structure

open.

They are to unblock and keep open tube-shaped structures in the body.

Stents


An intraluminal coronary artery

stent is a small, self-expanding,

metal mesh tube that is placed

inside a coronary artery after

balloon angioplasty to prevent

the artery from reclosing.

Risks of stents and stent placement may include:

Blood clot

Allergic reaction to stent material

Rupture of the duct or vessel when the stent is inserted

Stents


Further referencesFurther references

RATNER, B.; HOFFMAN A.; SCHOEN, F.; LEMONS, J.; “Biomaterials

Science”, 2nd Edition, Elsevier

DEE, K.; PULEO, D.; BIZIOS, R.; “ Tissue-Biomaterial Interactions”, Wiley

PARK, J.; LAKES, S.; “Biomaterials: An Introduction”, 3rd Edition, Springer

CALLISTER J., “Material Science and Engineering: An Introduction”, 6th

Edition, Wiley

GIL, H.; ROCHA, J.; BRANQUINHO, J.; ALVES, P.; CALVINHO, P.; “Polymeric

Biomaterials”, Open and Distance Learning for Training in Biotechnology,

Universidade de Coimbra

Further referencesFurther references

AcknowledgementAcknowledgement

For the content of this lecture:

Carlos Boto

Rita Gabriel

Eduardo Palmieri

Nathália Schmidt

Vinicius Magalhães

Joana Mendes

Mariline Alves

biomateriais #02 - introduction

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