Design, Fabrication, and Applications of DNA Nanomachines - DNA Nanotechnology: From Structure to Function - page 244

Fig. 11.15 ( a ) Illustrations of the controlled opening of the box lid (Reprinted by permission
from Macmillan Publishers Ltd: Ref. [ 14 ], copyright 2009). ( b ) Design of aptamer-gated DNA
nanorobot. Schematic front orthographic view of closed nanorobot loaded with a protein payload.
Two DNA-aptamer locks fasten the front of the device on the left and right . Payloads can be
loaded inside the nanorobot. The use of two different aptamers that “unlock” when exposed to
two antigens results in an AND logic gate, meaning that the nanobot opens in the presence of the
correct combination of antigen keys. The molecular payload is then released to bind to target cells
and activate signaling pathways (Reprinted by permission from Macmillan Publishers Ltd: Ref.
[ 91 ], copyright 2012)
domains that are covalently attached in the rear by single-stranded hinges and can
be noncovalently fastened in the front by staples modified with DNA aptamer-
based locks. The two strands of aptamers-complement duplex are incorporated on
the left and right sides of the front of the barrel, so that the aptamer strands are
attached to one domain and partially complementary strands are attached to the
other domain. Upon the addition of antigen keys, the aptamers-complement duplex
opens responsively, resulting in the opening of the two domains through entropic
spring. To ensure a high yield of its closed state, the nanorobot is equipped with two
“guide” staples adjacent to the lock sites that span the top and bottom domains of
the device. The guide staples contain 8-base toehold overhangs and can be removed
by strand displacement. Premodified with single-stranded DNA linkers, payloads
groups, such as 5 nm Au NPs and cell-targeted proteins, are loaded inside the
nanorobot. Series orthogonal experiments have been conducted to demonstrate that
only in the presence of both key in the solution and cell-targeted proteins inside the
nanorobot, the nanorobot can be opened and specifically bind to the labeled cells.
Another branch of the research has been conducted on utilizing DNA nanos-
tructure as carriers for metallic nanoparticles to fabricate 2D or 3D plasmonic