Biomedical Engineering Reference
In-Depth Information
TABLE 22.2
Main.Forces.Governing.the.Interfacial.Interactions.between.Nanomaterials.and.Biological.Systems
Force
OriginandNature
Range(nm)
PossibleImpactontheInterface
Hydrodynamic.
interactions
Convective.drag,.shear,.lift,.and.Brownian.diffusion.are.
often.hindered.or.enhanced.at.nanoscale.separations.
between.interacting.interfaces
10
2
-10
6
Increase.the.frequency.of.collisions.between.nanoparticles.and.
other.surfaces.responsible.for.transport
Electrodynamic.
interactions
VDW.interactions.arising.from.each.of.the.interacting.
materials.and.the.intervening.media
1-100
Universally.attractive.in.aqueous.media;.substantially.smaller.for.
biological.media.and.cells.owing.to.high.water.content
Electrostatic.
interactions
Charged.interfaces.attract.counter-ions.and.repel.co-ions.
through.Coulombic.forces,.giving.rise.to.the.formation.of.
an.electrostatic.double.layer
1-100
Overlapping.double.layers.are.generally.repulsive,.as.most.
materials.acquire.negative.charge.in.aqueous.media,.but.can.be.
attractive.for.oppositely.charged.materials
Solvent.
interactions
Lyophilic.materials.interact.favorably.with.solvent.
molecules
1-10
Lyophilic.materials.are.thermodynamically.stable.in.the.solvent.
and.do.not.aggregate
Lyophobic.materials.are.spontaneously.expelled.from.the.bulk.of.
the.solvent.and.forced.to.aggregate.or.accumulate.at.an.interface
Steric.interactions
Polymeric.species.adsorbed.to.inorganic.particles.or.
biopolymers.expressed.at.the.surfaces.of.cells.give.rise.to.
spring-like.repulsive.interactions.with.other.interfaces
1-100
a
Generally.increase.stability.of.individual.particles.but.can.
interfere.in.cellular.uptake,.especially.when.surface.polymers.
are.highly.water.soluble
Polymer.bridging.
interactions
Polymeric.species.adsorbed.to.inorganic.particles.or.
biopolymers.expressed.at.the.surfaces.of.cells.containing.
charged.functional.groups.can.be.attracted.by.oppositely.
charged.moieties.on.a.substrate.surface
1-100
Generally.promote.aggregation.or.deposition,.particularly.when.
charge.functionality.is.carboxylic.acid.and.dispersed.in.aqueous.
media.containing.calcium.ions
a.
Depending.on.the.length.of.adsorbed.or.expressed.polymeric.species.
