Biomedical Engineering Reference
In-Depth Information
of. chemotherapeutic. drugs. in. order. to. increase. the. overall. survival. rate. of. the. cancer.
patients..Similar.to.their.previous.studies.(Huang.et.al..2007),.Chow.et.al..have.recently.
shown.that.ND-DOX.can.overcome.drug.eflux.and.signiicantly.increases.apoptosis.in.
both.murine.liver.and.mammary.carcinoma.cell.models.(Chow.et.al..2011)..Apart.from.the.
tumor.growth.inhibition,.ND-DOX.exhibits.decreased.toxicity.in.vivo.compared.to.their.
standard.DOX.treatment..The.major.problem.of.DOX.is.that.the.drug.is.actively.efluxed.
from.the.tumor.cells.by.various.transporter.proteins..Reversibly.binding.of.DOX.to.ND.
with.the.NaOH.treatment.suggests.that.the.drug.can.be.slowly.released.both.in.vitro.and.
in.vivo..In.addition,.the.new.ND-DOX.system.shows.improved.drug.retention.in.tumor.
cells. with. improved. safety. and. eficacy. when. compared. to. the. DOX. treatment. alone.. It.
indicates.that.ND-conjugated.chemotherapeutics.is.a.promising.platform.for.overcoming.
chemoresistance.with.better.biocompatibility.and.eficacy.
25.5.4 ND for Dispersion of Water-insoluble Drugs
Poor. water. solubility. is. the. major. limitation. in. systemic. administration. of. some. drugs.
(Myrdal.and.Yalkowsky.2006)..To.address.this.issue,.Chen.et.al..have.reported.the.water.
solubilization.of.water-insoluble.drugs.after.being.combined.with.NDs.(Chen.et.al..2009)..
They. chose. purvalanol. A. and. 4-hydroxytamoxifen. (4-OHT). as. model. drugs,. which. are.
most. commonly. used. drugs. for. liver. and. breast. cancer. treatment. but. with. poor. water.
solubility.. It. is. shown. that. these. drugs,. when. complexed. with. ND. aggregates,. possess.
increasing. water. solubility.. Both. purvalanol. A. and. 4-OHT,. after. complexing. with. NDs,.
show.apparent.increase.in.zeta.potential.and.a.particle.size.reduction.by.three.orders.of.
magnitude. (∼100.nm).. The. increase. in. positive. charges,. accompanied. with. a. decrease. in.
size,.enhances.the.cellular.uptake.of.these.drug-loaded.nanoparticles.(Bettinger.et.al..1999,.
Kircheis.et.al..2001)..Similar.effects.have.been.demonstrated.with.the.anti-inlammatory.
drug,. Dexamethasone. (Chen. et. al.. 2009).. The. drug,. when. complexed. with. ND,. greatly.
increases.its.water.solubility.and.makes.the.complex.more.stable.in.aqueous.and.biological.
solution.
25.6 Conclusions and Future Perspectives
ND. is. a. new. member. of. the. nanocarbon. family,. holding. great. potential. and. promises.
for. applications. in. various. areas. of. science. and. technology.. This. chapter. provides. a.
critical.review.on.the.unique.features.of.ND,.including.good.biocompatibility,.multicolor.
emission. capability,. high. physical. and. chemical. stability,. and. excellent. photostability..
These.features.add.distinct.advantages.to.novel.applications.of.this.nanomaterial.in.life.
sciences..The.sp
3
-carbon-based.nanomaterial.can.not.only.serve.as.a.perfect.candidate.for.
biolabeling.and.long-term.cell.tracking.with.high.photostability,.but.also.can.be.applied.
as.a.biocompatible.vehicle.to.carry.and.deliver.drugs,.proteins,.and.genes.to.cells.or.whole.
animals..It.has.met.most.of.the.requirements.for.real-world.biological.applications.
A. multitude. of. limitations. still. need. to. be. overcome. before. subjecting. ND. for. clinical.
applications..For.example,.in.order.to.increase.the.dispersibility.of.bioconjugated.NDs.in.
physiological.media,.methods.to.properly.control.the.particle.size.and.surface.function-
alization.need.to.be.developed..As.the.interaction.of.NDs.with.biological.systems.greatly.
depends.on.cell.type,.animal.model,.and.route.of.administration,.a.close.comparison.of.
