The authors wish to thank S. Douglas for extremely valuable discussions and advice, and all the members of the Bachelet lab for helpful discussions and work. This work is supported by grants from the Faculty of Life Sciences and Institute of Nanotechnology &#38; Advanced Materials at Bar-Ilan University.

1. Preparation of Staples Pool Mixture
<ol>
	<li>Order lyophilized DNA nanorobot staples on 96-well plates as listed in Table 1 (see Materials) and normalize to 10 nmol. For a detailed description of the design and architecture of the DNA nanorobot see Ben-Ishay et al.14 and Douglas et al.15).</li>
	<li>Reconstitute each staple well with DNase/RNase-free ultrapure to a concentration of 100 &#181;M. For staples normalized to 10 nmol, reconstitute ...

<ol>
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The authors have nothing to disclose.

We described the fabrication, purification, and visualization of the DNA nanorobot. Following fabrication of the hexagonal chassis of the device, the function of the nanorobot is programmed with the simple introduction of specific cargo and sensing strands to the robot which readily find their designated position due to hydrogen-bonding complementarity with available single-strand docking sites14,15,22.
The fabrication protocol described uses a slow annealing ramp, which is generall...

The uses for nucleic acids nanotechnology are astounding. The tractability of the Watson-Crick base pairing as well as the ease and relative low-cost of large-scale synthesis of custom-made oligos2 has generated an explosion of applications3 and research in the field of DNA nanotechnology. Structural DNA nanotechnology, based on the immobile Seeman junction4,5 as a fundamental building block makes use of DNA as a self-assembling elementary unit for the construction of arbitrary shapes6-8.
The recent development of the scaffolded DNA origami9 technique allows for the construction of complex 2D/3D nano-architectures10-12 with sub-nanometer precision and is an efficient route for building new functional objects with increasing complexity and astonishing diversity. The construction process is based upon a long scaffold single stranded DNA, usually derived from a viral genome, which can be folded through the hybridization of hundreds of short single strand DNA oligos termed staples. The high structural resolution obtained by this technique is the direct result of the natural dimensions of the DNA double helix, while the reproducibility of fabrication is the result of tailoring the short single-strand staple sequences to facilitate the maximum hydrogen-bonding complementarity achievable. With the use of a slow temperature annealing ramp the designed lowest-energy, thermodynamically preferred nanostructure is reached in high yields and fidelity. The easy implementation of junction design rules in a computer code enabled the development of CAD tools, such as caDNAno13, that extremely simplify the task of designing large, complex structures containing hundreds of connected junctions.
Previously we described the design of a DNA nanorobot with the aid of the caDNAno tool14,15. Here we depict the fabrication and visualization, via transmission electron microscopy (TEM), of the nanorobot, a 3D hollow hexagonal nanodevice, with dimensions of 35 x 35 x 50 nm3, designed to undergo a major conformational change in response to a predetermined stimuli and present specific cargo, such as proteins or nucleic acid oligos, sequestered inside. While 12 loading stations are available inside the hollow chassis, the actual number of bound cargo differs with cargo size. Cargo molecules range from small DNA molecules to enzymes, antibodies and 5-10 nm gold nanoparticles. Cargocan either be uniform or heterogeneous, such that each nanorobot contains a mixture of different molecules. Sensing is achieved via two double helical locking gates design to sense proteins, nucleic acids or other chemicals, based either on aptasensor16,17 or DNA strand displacement18 technologies. Recent developments in aptamer selection protocols19-21 enable the design of nanorobots responding to an ever increasing range of molecules and cell types.
Earlier work showed a nanorobot carrying a specific antibody, which upon binding to its antigen can relay either an inhibitory or a prolific signal to the inside of specific cell types in a mixed cell population15. An exciting feature of these nanodevices is their ability to perform even more complex tasks and logic control with the introduction of different nanorobot subtypes in a single population. Recently we demonstrated specific subtypes of nanorobots performing as either positive or negative regulators, controlling an effector population containing an active cargo molecule22.
The protocol presented here describes the fabrication, purification and imaging of a nanorobot gated with aptamer sensor sequences which bind selectively to PDGF to facilitate the opening of the nanorobot15,22. The fabrication process described is similar to the nanorobot fabrication process initially depicted by Douglas et al.15 with changes aimed at reducing overall process duration, while increasing the yield and purification rates.

<table>
	<tbody>
		<tr>
			<td>DNase/RNase free distilled water</td>
			<td>Gibco</td>
			<td>10977</td>
		</tr>
		<tr>
			<td>M13mp18 ssDNA scaffold</td>
			<td>NEB</td>
			<td>N4040S</td>
		</tr>
		<tr>
			<td>10x TAE</td>
			<td>Gibco</td>
			<td>15558-042</td>
		</tr>
		<tr>
			<td>1 M MgCl2</td>
			<td>Ambion</td>
			<td>AM9530G</td>
		</tr>
		<tr>
			<td>Amicon Ultra 0.5 mL centrifugal filter 100K MWCO</td>
			<td>Amicon</td>
			<td>UFC510024</td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Promega</td>
			<td>V3125</td>
		</tr>
		<tr>
			<td>TBE buffer</td>
			<td>Promega</td>
			<td>V4251</td>
		</tr>
		<tr>
			<td>Ethidium bromide 10mg/ml solution&#160;</td>
			<td>Sigma Aldrich</td>
			<td>E1510</td>
		</tr>
		<tr>
			<td>1 kb DNA marker</td>
			<td>NEB</td>
			<td>N3232S</td>
		</tr>
		<tr>
			<td>Loading Dye</td>
			<td>NEB</td>
			<td>B7021S</td>
		</tr>
		<tr>
			<td>uranyl formate</td>
			<td>polysciences</td>
			<td>24762</td>
		</tr>
		<tr>
			<td>carbon-coated TEM grids&#160;</td>
			<td>Science services</td>
			<td>EFCF400-Cu-50</td>
		</tr>
		<tr>
			<td>Thermal Cycler c1000 Touch</td>
			<td>Bio-Rad</td>
			<td></td>
		</tr>
		<tr>
			<td>Glow Discharge K100X</td>
			<td>Emitech</td>
			<td></td>
		</tr>
		<tr>
			<td>UV table Gel Doc EZ Imager</td>
			<td>Bio-Rad</td>
			<td></td>
		</tr>
		<tr>
			<td>NanoDrop 2000c</td>
			<td>Thermo Scientific</td>
			<td></td>
		</tr>
		<tr>
			<td>TEM FEI-G12</td>
			<td>Tecnai</td>
			<td></td>
		</tr>
	</tbody>
</table>

folding and characterization of a bio-responsive robot from dna origami

The DNA nanorobot is a hollow hexagonal nanometric device, designed to open in response to specific stimuli and present cargo sequestered inside. Both stimuli and cargo can be tailored according to specific needs. Here we describe the DNA nanorobot fabrication protocol, with the use of the DNA origami technique. The procedure initiates by mixing short single-strand DNA staples into a stock mixture which is then added to a long, circular, single-strand DNA scaffold in presence of a folding buffer. A standard thermo cycler is programmed to gradually lower the mixing reaction temperature to facilitate the staples-to-scaffold annealing, which is the guiding force behind the folding of the nanorobot. Once the 60 hr folding reaction is complete, excess staples are discarded using a centrifugal filter, followed by visualization via agarose-gel electrophoresis (AGE). Finally, successful fabrication of the nanorobot is verified by transmission electron microscopy (TEM), with the use of uranyl-formate as negative stain.

Representative results are shown in Figure 2A. All lanes contain 1 &#181;g of total DNA, measured via spectrophotometer (OD260). Compared with the circular single-strand DNA scaffold (Lane 2), nanorobots are hindered in the gel due to their higher molecular weight, the result of staples hybridization to the scaffold DNA (Lane 3. Red arrow). The low molecular weight band in Lane 3 represents excess staples which did not bind to the scaffold DNA (Green arrow). After purification via centrifugal ...

Watch this Scientific Journal Video about Folding and Characterization of a Bio-responsive Robot from DNA Origami at JoVE.com

Folding and Characterization of a Bio-responsive Robot from DNA Origami

DNA origami is a powerful method for fabricating precise nanoscale objects by programming the self-assembly of DNA molecules. Here we describe a protocol for the folding of a bio-responsive robot from DNA origami, its purification and negative staining for transmission electron microscopic imaging (TEM).

The DNA nanorobot is a hollow hexagonal nanometric device, designed to open in response to specific stimuli and present cargo sequestered inside. Both ...

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14.4K Görüntüleme.  Bar-Ilan University. DNA origami is a powerful method for fabricating precise nanoscale objects by programming the self-assembly of DNA molecules. Here we describe a protocol for the folding of a bio-responsive robot from DNA origami, its purification and negative staining for transmission electron microscopic imaging (TEM). 