Nanorobotic arm to operate within DNA sequence
Kristina Kirby
By Michael Berger
Nanorobotic arm to operate within DNA sequence
(Nanowerk Spotlight) The success of nanorobotics requires the precise
placement and subsequent operation of specific nanomechanical devices
at particular locations, thereby leading to a diversity of structural
states. The structural programmability of DNA makes it a particularly
attractive system for nanorobotics. A large number of DNA-based
nanomechanical devices have been described, controlled by a variety of
methods. These include pH changes and the addition of other molecular
components, such as small molecule effectors, proteins and DNA
strands. The most versatile of these devices are those that are
controlled by DNA strands. This versatility results because they can be
addressed specifically by strands with particular sequences.
Researchers at New York University have developed a framework that
contains a binding site - a cassette - that allows insertion of a
rotary device into a specific site of a DNA array, allowing for the
motion of a nanorobotic arm. Changing the cassette's control
sequences or insertion sequences allows the researchers to manipulate
the array or insert it at different locations.
"We have developed a cassette that enables us to direct a device to a
particular place in an array" Dr. Nadrian C. Seeman, professor at NYU's
Chemistry Department, explains to Nanowerk. "This is the first time
that a sequence-dependent DNA-based nanomechanical device has been
targeted to a specific site in a 2D lattice. This means that ultimately
a variety of devices which can be in multiple states, and which are
individually addressable, can be organized in lattices, with a large
number of states associated with them. The two states of this device
can be distinguished by atomic force microscopy."
The insertion of such nanomechanical devices into 2D arrays results in
a nanorobotic system, wherein nanoscale moving parts can be controlled
relative to a fixed frame of reference.
Seeman points out that the results pave the way for creating nanoscale
'assembly lines' in which more complex maneuvers could be executed.
The results are based upon a device Seeman and (then) NYU graduate
student Hao Yan had previously developed (Yan is now a professor at
Arizona State University). That component has enabled the translation
of DNA sequences, thereby potentially serving as a factory for
assembling the building blocks of new materials. The invention has the
potential to develop new synthetic fibers, advance the encryption of
information, and improve DNA-based computation.
Another previous device, developed with NYU Chemistry graduate student
Shiping Liao, contains two PX-JX2 devices and emulates the process by
which RNA replicas of DNA sequences are translated to create protein
sequences. However, the signals that control the nanomechanical tool
are DNA rather than RNA. The dimensions of the machine are
approximately 110 x 30 x 2 nm.
"It is crucial for nanorobotics to be able to insert controllable
devices into a substrate, thereby leading to a diversity of structural
states" says Seeman. "Here we have demonstrated that a single device
has been inserted and converted at a specific site. There is no reason
to expect that the system is limited to a single device unit."
Seeman's latest findings have been reported in Science "Operation of a
DNA Robot Arm Inserted into a 2D DNA Crystalline Substrate".
Also see our previous Nanowerk Spotlight that highlights the control of
the PX-JX2 device by RNA. This method was used in the above work as
well.
By Michael Berger, Copyright 2007 Nanowerk LLC