Biomedical Engineering Reference
In-Depth Information
30°
60°
Limiting of channels
0°
90°
135°
iii
ii
0°
i
Inducing of nanofiber surface
Figure 21.3
(See companion CD for color igure.)
The.schematic.of.microluidic.chip.integrated.with.electrospun.nanoiber.
surface.for.the.investigation.of.cell.orientation.under.combined.effects.
growth. paths. and. the. formation. of. branches. (Withers. et. al.. 2006).. Bryan. Kaehr. demon-
strated.the.guidance.of.neuron.interconnection.formation.and.neurite.extension.with.the.
assistance.of.multiphoton.cross-linking.3D.protein.line.(Kaehr.et.al..2004).
Due.to.the.nanoscale.size.of.peptides.or.protein.molecules,.the.self-assembled.nanoibers.
of.peptide.amphiphile.can.reach.as.small.as.10.nm.in.diameter..This.type.of.ECM.recreation.
with.hydrophobic.and.hydrophilic.properties.promotes.cell.proliferation,.differentiation,.
migration,.etc..(Xu.et.al..2008,.Rexeisen.et.al..2010)..Peptides.conjugating.with.ECM.can.bind.
to.integrin.receptors.as.adhesion.ligands,.and.this.organized.complex.mediates.several.
cell. behaviors. such. as. spreading. and. differentiation.. Peptide. like. arginine-glycine-
aspartic. acid. (or. RGD). forms. a. high-density. complex. with. a. matrix. of. a. nanopatterned.
island. of. 30-70.nm. in. diameter.. Besides. experiments. of. osteoblast. responses. to. ligand.
nanopatterns,.a.computational.model.of.integrin.binding.to.the.ligand.nanopattern.and.
the. generation. of. integrin. organization. in. silico. has. been. quantiied.. The. experiments.
demonstrated.that.engineering.biomaterials.at.the.nanometer.scale.correlates.to.MC3T3.
preosteoblast.cell.spreading.and.differentiating.with.integrin's.distribution.status..These.
results. indicated. the. complicated. mechanisms. linking. integrin. organization. to. cell.
response.(Comisar.et.al..2011).
A.nanotube.is.a.nanometer-scale.tube-like.structure.with.different.material.composition.
such.as.carbon.nanotube,.inorganic.nanotube,.and.DNA.nanotube..Nanotubes.with.cer-
tain.sizes.and.modiied.surface.biocompatibility.offer.a.suitable.platform.for.cell.structure.
and.functional.investigation..For.example,.TiO
2
.nanotube.surfaces,.which.are.formed.by.
the.modiication.with.the.covalent.immobilization.of.two.bioactive.molecules,.epidermal.
growth.factor.(EGF).and.bone.morphogenetic.protein-2.(BMP-2),.have.been.demonstrated.
to.affect.the.behavior.of.mesenchymal.stem.cells.(MSCs).directly..MSCs.show.good.cell.
viability.and.proliferation.at.the.TiO
2
.nanotube.of.100.nm.in.diameter.with.EGF.or.BMP-2,.
but.strong.apoptosis.is.apparent.with.no.modiication.in.this.size.of.TiO
2
.nanotube.(Bauer.
et.al..2011).
Micro/nanotechnology. facilitates. the. exploration. of. cell. biophysical. processes. and.
mechanisms.. Microluidics. is. a. powerful. platform. to. investigate. chemical. synthesis,.
biomaterial.droplet.control,.and.cell.culture.with.precise.spatial.and.temporal.coninement..
According.to.the.microscale.fabrication,.the.match.of.cell.size.with.3D.matrix.culture.exhibits.
benign. microenvironments. for. the. study. of. integrative. biology.. Beebe. and. colleagues.
presented.a.microluidic.3D.in.vitro.model.that.exhibited.breast.cancer.progression.from.
noninvasive. to. invasive. status,. with. the. control. of. the. microenvironment. both. temporal.
