Biomedical Engineering Reference
In-Depth Information
a. nanoscaffold. for. growing. skin. cells,. neural. cells,. chondrocytes,. and. enteric. nervous.
system.(ENS).cells..At.the.end.of.the.study,.they.concluded.that.their.method.was.effective.
for.both.cell.growth.and.cell.viability.
15.2.4 Biological Chemistries and Manipulations
Besides. the. use. of. new. materials. for. nanobiotechnology,. there. are. also. many. different.
kinds. of. chemistries. and. biological. manipulations. being. employed. for. use. in. this. ield..
Many.naturally.occurring.reactions,.such.as.substrate.channeling,.are.being.studied.and.
exploited.for.use.in.a.variety.of.new.chemical.processes..Conjugations.of.chemistry.with.
biology.are.also.being.used.to.improve.biological.separations.and.detection.of.proteins.
15.2.4.1 Substrate Channeling
A. type. of. manipulation. that. is. being. explored. is. substrate. channeling.. Substrate.
channeling. occurs. when. the. intermediate. product. from. an. enzyme. is. transferred. to.
another. neighboring. enzyme. without. allowing. the. intermediate. to. equilibrate. in. the.
bulk. phase. (Spivey. and. Ovádi. 1999).. This. process. can. occur. in. vivo,. ex. vivo,. or. in. vitro.
naturally,. but. there. are. many. beneits. to. constructing. synthetic. complexes. for. substrate.
channeling. for. biotechnology. purposes. (Zhang. et. al.. 2011).. Substrate. channeling. allows.
for. faster. reaction. rates. when. compared. to. free. loating. enzymes,. as. well. as. protecting.
unstable. intermediates,. obstructing. substrate. competition. among. different. pathways,.
and.enhancement.of.biocatalysis.by.avoiding.unfavorable.energetics.of.substrates..Some.
of. these. synthetic. complexes. include. multifunctional. fusion. proteins,. complexes. linked.
with. scaffolding,. synthetic. cellulosomes. and. recombinant. cellulolytic. microorganisms,.
and.the.co-immobilization.of.multiple.enzymes,.all.of.which.can.be.seen.in.Figure.15.3..
A.co-immobilized.enzyme.complex.was.formed.by.coupling.the.enzymes.to.the.surface.
of.isocyanopeptides.and.styrene.for.use.as.nanoreactors.(Van.Dongen.et.al..2009)..These.
nanoreactors.were.multistep,.irst.converting.glucose.acetate.to.glucose,.and.then.oxidizing.
glucose. into. gluconolactone. with. hydrogen. peroxide. as. a. byproduct.. At. the. end. of. the.
study. it. was. concluded. that. the. co-immobilized. enzyme. cascade. allowed. for. a. faster.
reaction.rate.of.these.conversions.
15.2.4.2 Chemical Tags
The. Nano-Tag. is. one. of. the. many. ways. in. which. nanoscale. chemistry. applications. are.
being.applied.to.biology..The.Nano-Tag.is.a.streptavidin-binding.peptide.that.is.15.amino.
acids. long. and. has. an. afinity. for. streptavidin.. This. chemistry. has. been. used. for. puri-
ication. and. detection. of. recombinant. proteins. (Lamla. and. Erdmann. 2004).. Lamla. and.
Erdmann. developed. the. Nano-Tag. and. then. sought. to. study. its. eficiency. in. one-step.
protein.puriication..They.found.that.the.Nano-Tag.was.capable.of.one-step.protein.puri-
ication. and. that. it. could. be. subsequently. used. for. detection. on. a. western. blot. using.
streptavidin.reagents.
Another.chemistry.being.employed.for.biological.uses.is.avidin..Avidin.is.a.biotin-binding.
protein.typically.used.as.a.protein-puriication.component.for.biotin-labeled.proteins.or.
nucleic.acids..In.a.study.conducted.by.Fang.et.al.,.avidin.was.connected.to.a.glassy.carbon.
electrode..Using.this.as.a.base,.they.were.successfully.able.to.create.a.quantitative.electro-
chemiluminescence.detector.(Fang.et.al..2008)..Biontinylated.bovine.serum.albumin.(BSA),.
which.was.labeled.with.tris(2,2-bipyridine).ruthenium(II),.was.then.attached.to.the.avidin.
