Biomedical Engineering Reference
In-Depth Information
and. lab-on-a-chip. systems. (Hiyama. and. Moritani,. 2010).. Potential. applications. will. be.
greatly.enhanced.by.the.increased.knowledge.of.working.with.these.motors.
4.4.2 reverse engineering Nature
The. success. of. reverse. engineering. nature. for. generating. biosynthetic. devices. increases.
as. our. knowledge. of. cellular. mechanisms. expands. to. allow. us. to. take. advantage. of.
what. intricacies. evolution. has. perfected. over. billions. of. years.. This. generally. requires.
combining. studies. that. span. several. disciplines. from. molecular. biology,. biochemistry,.
and. cell. biology. to. mathematical. modeling,. integrated. circuit. fabrication,. engineering.
technology,.and.design..There.is.sound.reason.to.apply.nature's.nanomachinery.toward.
new.synthetic.applications..As.devices.scale.down,.the.ability.to.which.we.can.precisely.
manipulate. objects. becomes. impaired.. Force. constraints. change. as. well.. The. dominant.
force. below. 100.nm. is. passive. transport,. whereas. luid. low. is. the. primary. method. for.
active.transport.at.sizes.10.μm.and.larger..It.is.from.sub-nanometer.through.this.middle.
regime.between.100.nm.and.10.μm.that.active.transport.with.molecular.machines.operates..
Additional.advantages.of.these.molecular-driven.devices.include.minimal.mass.and.much.
lower. energy. cost. while. increasing. functionality.. A. summary. of. applications. of. motor.
proteins.and.cytoskeletal.components.in.nanodevices.is.shown.in.Table.4.1.
Perhaps,.one.of.the.greatest.challenges.to.applying.molecular.components.to.biosynthetic.
devices.in.vitro.is.how.to.obtain.suficient.material.of.the.cellular.component.of.interest.
through. molecular. biochemical. isolation.. In. DNA. origami. (Endo. and. Sugiyama,. 2011;.
Tørring. et. al.,. 2011),. the. simplicity. of. DNA. structures. along. with. current. advanced.
technology. for. DNA. synthesis,. generating. modiications,. and. sequencing,. greatly.
simpliies. attainment. of. suficient. biological. material.. Working. with. Kinesin,. Klps,.
and. microtubules. is. a. greater. challenge. due. to. their. inherent. complexity.. Great. interest.
surrounding.the.mechanisms.of.motors.and.microtubules.and.their.cellular.roles.has.led.
to.reined.protocols.for.their.isolation;.however,.bulk.isolation.protocols.may.need.further.
reinement.. In. addition,. regulation. of. these. proteins. remains. complex.. Tubulin. is. often.
puriied.from.bovine.brain.tissue.using.a.process.of.polymerization.and.depolymerization.
to.ensure.removal.of.MAPs..If.no.genetic.manipulation.of.the.components.is.required,.they.
may. be. purchased,. though. the. cost. over. time. can. be. formidable.. Protein. modiications.
inluence.function.and.may.be.important.elements..Protein.stability.remains.a.challenge..
Once.isolated,.proteins.may.be.lyophilized.or.frozen.for.stability.and.retained.activity.until.
use..Isolation.and.activity.irst.require.optimization.of.the.appropriate.buffer.conditions,.
including. pH,. salts,. ATP,. GTP,. and. protease. inhibitors.. Temperature. is. also. a. factor.. In.
the. medical. ield,. optimizing. protein. stability. for. pharmaceuticals. to. generate. “shelf.
stable”.characteristics.is.often.required.(for.review,.see.Zakrzewska.et.al.,.2011)..Similarly.
through.genetic.engineering,.the.bio-components.of.proof-of-concept.biosynthetic.devices.
can.be.engineered.to.a.more.stable.form.that.will.retain.key.dynamic.features..Studies.of.
conserved. proteins. derived. from. organisms. living. under. extreme. conditions. of. heat. or.
cold.are.often.informative.
The.self-assembling.features.of.motors.and.microtubules.mean.that,.once.mixed,.the.
components. will. interact. dynamically. and. begin. to. assemble. complex. architectures..
A.manner.in.which.to.regulate.the.system.must.be.considered..Microtubules.and.their.
motors.have.long.been.targets.of.small.molecule.chemotherapy.(Jordan.and.Wilson,.2004;.
Huszar. et. al.,. 2009).. Useful. drugs. include. microtubule. stabilizers. such. as. paclitaxel,. or.
destabilizers.such.as.vincristine.or.vinblastine,.or.thiabendazole.for.fungal.microtubules..
