Biomedical Engineering Reference
In-Depth Information
Fig. 11.14
(
a
) The operation cycle of the aptamer-based molecular machine in the presence of
thrombin. (
b
) Switchable DNA nanocontainer triggered by pH change (Reprinted with permission
from Ref. [
86
]. Copyright 2007 Oxford Journals). (
c
) A DNA tetrahedron with a single reconfig-
urable edge. Four strands are combined to form tetrahedron. The edge is extended by adding a fuel
hairpin and contracted by the antifuel hairpin (Reprinted by permission from Macmillan Publishers
Ltd: Ref. [
88
], copyright 2008)
including the convenience of modification on DNA terminals, the addressable
carrying sites based on DNA sequence specificity, and the controllable conformation
changes of 2D even 3D DNA nanomachines, make them excellent candidates for
applications on molecule carriers for drug delivery and nanoparticle transport for
engineerable assemblies.
The first strategy was used by Simmel to grab or release the human blood-clotting
factor,
-thrombin, using the DNA-aptamer-based machine [
84
](Fig.
11.14
a). One
fuel strand can disrupt the interaction between the aptamer (G-quadruplex) and the
thrombin by energetically favored hybridization, and the other fuel strand has higher
affinity to the “disrupting” strand, re-forming the thrombin-aptamer complex. In the
'
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