Biomedical Engineering Reference
In-Depth Information
by.ive.40-nucleotide.oligomers.(Shih.et.al..2004,.He.et.al..2010)..Assembly.was.carried.out.
at.a.100.nM.concentration.of.the.template.strand,.and.fourfold.excess.of.each.oligo,.in.pH.
7.5.buffer.with.10.mM.Mg
2+
..The.octahedron.self-assembled.in.about.50%.yield,.as.judged.
by. a. gel-mobility. shift. assay.. Unlike. the. earlier. DNA. cube. and. truncated. octahedron.
produced.by.the.Seeman.group,.this.structure.did.not.require.ligation.steps.(there.are.no.
closed. loops. of. DNA),. which. probably. contributes. to. the. improved. assembly. yield.. The.
structure.was.determined.by.cryo-electron.microscopy,.which.revealed.a.22.nm.diameter.
hollow.octahedron.whose.DNA.struts.were.clearly.delineated..A.similar.assembly.process.
generated. tetrahedra,. which. could. be. decorated. with. attachment. sites. for. non-DNA.
components.at.desired.locations.(Sun.et.al..2009,.Wong.et.al..2011)..Tensegrity.structures.
(Figure.1.7).can.also.be.made.from.DNA,.using.duplex.bundle.structures.as.rods.and.ss.
regions.or.single.duplexes.as.“string”.(Liu.et.al..2004,.Leidl.et.al..2010)..Forces.of.about.5-10.
pN. can. be. applied. by. the. tension. of. the. duplex. DNA. “strings.”. By. including. restriction.
sites.in.the.“string”.regions,.Leidl.et.al..were.able.to.cut.speciic.strings.enzymatically.in.
order.to.reconigure.the.shapes.of.some.of.the.tensegrity.structures.
i
iii
iii
ii
ii
i
(a)
(b)
(c)
(d)
(e)
Figure 1.7
(See companion CD for color igure.)
.Tensegrity.structures..(a).macroscopic.tensegrity.structure,.(b).layout.of.
DNA.origami.template.strand,. (c).schematic. 3D.structure.of.DNA.object,.(d).details.of.3-helix.strut,.(e).cryo-
electron.microscopy.images.of.DNA.tensegrity.structures.in.different.orientations..(Reprinted.by.permission.
from.Macmillan.Publishers.Ltd..
Nat. Nanotechnol
.,.Leidl,.T..et.al.,.Self-assembly.of.three-dimensional.prestressed.
tensegrity.structures.from.DNA,.5,.520-524,.Copyright.2010.)
