Biomedical Engineering Reference
In-Depth Information
TABLE 8.1
Characteristics.of.Docetaxel-Loaded,.Trastuzumab-Functionalized.Nanoparticles.
of.PLA-TPGS.and.TPGS-COOH.Copolymer.Blend.at.Various.Component.Ratios
Nanoparticles
Size(nm)
Polydispersity
ZetaPotential(mV)
EE(%)
NP0
301.8.±.9.5
0.143.±.0.02
-42.73.±.3.88
54.7.±.4.73
NP10
294.7.±.9.2
0.151.±.0.03
-41.68.±.4.12
55.8.±.4.62
NP10-HER
308.5.±.9.0
0.202.±.0.03
-32.25.±.2.95
54.5.±.6.25
NP20
286.2.±.10.2
0.156.±.0.03
-40.33.±.4.01
57.4.±.4.19
NP20-HER
305.7.±.11.8
0.175.±.0.05
-25.08.±.1.15
55.7.±.5.75
NP33
292.5.±.9.8
0.121.±.0.03
-41.50.±.3.28
48.2.±.4.03
NP33-HER
311.2.±.9.4
0.155.±.0.04
-23.94.±.2.09
47.5.±.4.58
Source:
.
Reproduced.with.permission.from.Sun.et.al.,.
Nanomedicine
.4(4):.431-445,.2009.
in. diameter. would. be. appropriate. to. be. used. as. drug. carriers. to. achieve. high. cellular.
uptake. through. a. mechanism. called. endocytosis,. in. which. the. individual. nanoparticle.
would.irst.adhere.to.the.cell.surface.and.then.bend.a.small.piece.of.the.lipid.bilayer.mem-
brane.. The. nanoparticles. would. then. be. enveloped. and. engulfed. into. the. cytoplasm.. In.
this. process,. the. surface. energy. of. the. NPs. is. sacriiced. to. provide. the. bending. energy..
Too. small. NPs. would. not. have. enough. surface. energy. to. complete. the. cell. membrane.
bending.process..Moreover,.too.small.NPs.would.result.in.too.small.drug.encapsulation.
eficiency.and.cause.too.fast.drug.release..We.found.that.placebo.nanoparticles.have.simi-
lar.sizes.and.size.distributions.as.their.corresponding.drug-loaded.nanoparticles..Other.
physicochemical.properties,.such.as.surface.morphology,.surface.chemistry,.and.surface.
charge,.were.also.not.effected.by.the.drug.loading.since,.as.the.XPS.investigation.shows.
in.Section.8.5.5,.no.drug.molecules.appear.on.the.nanoparticle.surfaces.due.to.their.high.
hydrophobicity.
8.5.2 Surface Morphology
The.surface.morphology.of.the.docetaxel-loaded.PLA-TPGS/TPGS-COOH.NPs.was.inves-
tigated. by. a. ield. emission. scanning. electron. microscopy. system. (FESEM;. JSM-6700F,.
JEOL,.Tokyo,.Japan)..The.samples.were.prepared.by.dripping.a.drop.of.the.NP.suspension.
onto.the.copper.tape.placed.on.the.surface.of.the.sample.stub.and.drying.it.overnight..The.
stub.was.coated.with.a.platinum.layer.by.the.Auto.Fine.Platinum.Coater.(JEOL).for.40.s.
before.measuring.
Figure 8.3.shows.the.surface.morphology.of.the.docetaxel-loaded.PLA-TPGS/TPGS-
COOH.NPs,.and.the.images.were.studied.by.FESEM..The.docetaxel-loaded.NPs.with-
out. trastuzumab. modiication. (Figure 8.3A). were. spherical. in. shape. with. a. smooth.
surface.within.the.FESEM.resolution.level..The.image.of.NPs.with.trastuzumab.conju-
gation.had.a.blurry.surface,.and.there.seemed.to.be.adhesion.between.the.NPs,.com-
pared.with.NP20,.which.was.probably.caused.by.the.trastuzumab.on.the.nanoparticle.
surface.
8.5.3 Surface Charge
Zeta.potential.is.an.important.factor.to.determine.the.stability.of.the.NPs.in.dispersion..
Surface.charge.also.plays.an.important.role.in.the.interaction.between.the.cell.membrane.
