Biomedical Engineering Reference
In-Depth Information
substitute.a.tissue.or.organ.of.a.living.system.that.is.not.fully.functioning,.or.to.support.
the.biological.system.in.its.function.while.in.intimate.contact.with.the.tissues.in.a.safe,.reli-
able,. economic,. and. physiologically. acceptable. manner. (Park. and. Bronzino,. 2003).. Black.
(1999).deined.biomaterial.as.“a.nonviable.material.used.in.a.medical.device,.intended.to.
interact.with.biological.systems.”.In.addition,.during.the.Second.Consensus.Conference.
on.Deinitions.in.Biomaterials.Science,.a.biomaterial.was.deined.as.“a.material.intended.
to.interface.with.biological.systems.to.evaluate,.treat,.augment,.or.replace.any.tissue,.organ.
or. function. of. the. body”. (Williams. et. al.,. 1987;. Williams,. 1992).. The. same. deinition. is.
found.in.the.
Williams Dictionary of Biomaterials
.(Liverpool.University.Press,.1999).
Biomaterials.are.used.in.many.application.areas,.such.as.orthopedic.(total.joint.replace-
ments,.bone.plates.and.screws,.etc.),.dental.(tooth.illings,.crowns,.implants,.etc.),.cardio-
vascular.(cardiac.pacemaker,.artiicial.heart.valve,.blood.vessels,.etc.),.ophthalmic.(contact.
and.intraocular.lenses),.wound.healing.(sutures,.wound.dressing,.tissue.adhesive,.ligating.
clips,.staples,.etc.),.and.drug.delivery.(oral,.inhalation.injectable.delivery.systems,.micro-.
and.nanodevices,.sheets,.ibers,.and.sponges,.etc.).systems..Biomaterials.can.be.found.in.
different.forms,.such.as.tubes.(artiicial.veins,.artiicial.trachea),.ibers.(sutures),.ilms.and.
membranes.(wound.dressings,.drug.delivery.systems,.artiicial.kidney),.gels.(burn.covers,.
topical.drug.delivery.systems),.and.porous.scaffolds.(tissue.engineering),.depending.on.the.
site.and.type.of.use..Metals.(titanium,.stainless.steel,.cobalt-chromium.alloys,.gold,.silver,.
platinum),. polymers. (nylon,. silicones,. Telon,. dacron,. polylactides),. ceramics. (aluminum.
oxide,.carbon,.hydroxyapatite),.natural.materials.(collagen,.hyaluronic.acid,.reconstituted.
tissue.such.as.porcine.heart.valves),.and.composites.(carbon.or.ceramic.wires,.iber-rein-
forced.polymers).have.been.used.as.biomaterials.in.the.design.and.production.of.biomedi-
cal.devices..Material.to.be.used.as.a.biomaterial.must.fulill.some.requirements..First,.it.
should.be.compatible.with.the.biological.environment.and.should.not.cause.any.adverse.
carcinogenic.or.allergic.tissue.reaction;.i.e.,.it.should.be.biocompatible..Degradation.prod-
ucts. of. a. biomaterial. must. also. be. nontoxic. and. noncarcinogenic,. and. have. the. desired.
bioactivity.toward.the.cells.and.tissue..Physical,.chemical,.and.mechanical.properties.of.
the.biomaterial.should.match.those.of.the.target.tissue.
10.2 TissueEngineering
Tissue.engineering.was.once.considered.a.subield.of.biomaterials,.but.since.it.has.gained.
too.much.importance.in.the.last.decades,.it.is.now.considered.a.ield.in.its.own.right..Tissue.
engineering. is. the. process. of. creating. living. three-dimensional. (3D). tissues. and. organs.
by.using.engineering.and.materials.methods,.and.speciic.combinations.of.cells.and.cell.
signals,.both.chemical.and.mechanical.(Grifith,.2002)..This.approach.aims.to.reproduce.
both. the. form. and. function. of. the. tissue.. Different. from. nonliving. biomaterials,. tissue.
engineering.is.based.on.the.formation.and.regeneration.of.a.new.functional.tissue.by.com-
bining.living.components.(cells,.tissue.fragments).and.carrier.scaffolds.in.a.construct.to.be.
implanted.into.the.body.(Kneser.et.al.,.2002;.Guelcher.et.al.,.2006).
There.are.three.approaches.in.repairing.tissues.(Langer.et.al.,.1993;.Ma,.2004b)..The.irst.
one.is.the.injection.of.tissue-speciic.viable.cells.directly.into.the.damaged.site.of.the.tis-
sue.. The. second. approach. is. the. delivery. of. tissue-inducing. substances,. such. as. growth.
