## 5 Conclusions and Perspectives  
\"What are the possibilities of small but movable machines? They may or may not be useful, but they surely would be fun to make,\" pondered [PERSON] in his talk [1]. Here, we reviewed DNA origami-based nanomachines that exhibit translational and rotational motion when triggered by various types of stimuli. We also addressed [PERSON]'s question by discussing the usefulness of these nanomachines. The summary of stimuli/interactions, implementations, and possible applications reviewed in this article are listed in Table 1.  
Figure 3: DNA origami movement using stimuli. (**a**) A spherical DNA origami container that can be opened by light [100]; (**b**) Reconfigurable chiral plasmonic metamolecules [103]; (**c**) A thermoresponsive actuator [106]; (**d**) An autonomous nanoscopic force clamp [107]. (**e**) An electric-field-directed robotic arm [43]. (**f**) Magnetic actuators; a lever system and a rotor [111]. (**a**) is reproduced with permission from the authors of [100], copyright The Royal Society of Chemistry, 2015; (**b**) is reproduced with permission from the authors of [103], published by The American Association for the Advancement of Science, 2017; (**c**) is reproduced with permission from the authors of [106], copyright John Wiley and Sons, 2018; (**d**) is reproduced with permission from the authors of [107], copyright The American Association for the Advancement of Science, 2016; (**e**) is reproduced with permission from the authors of [43], copyright The American Association for the Advancement of Science, 2018; (**f**) is reproduced with permission from the authors of [111], published by Nature Publishing Group, 2018. \begin{table}
\begin{tabular}{c c c} \hline
**Interaction/Stimulus** & **Implementation** & **Application** \\ \hline  & & Containers [15,60,61] \\  & & Biosensing [63] \\  & & Reconfigurable plasmonics [79] \\ DNA oligonucleotides & Lock-key systems based on tohold-mediated strand displacement & Reconfigurable actuators and lattices [70,71] \\  & Transient binding & DNA point accumulation for imaging in nanoscale topography (DNA-PAINT) [81, 82, 83] \\  & & Robotic values [42] \\  & & Rotary devices [62] \\ \hline Entropic elasticity and steric effects & ssDNA as an entropic spring & Nanomechanical devices [63, 64, 65, 66, 67] \\  & & Force spectrometers [107] \\ \hline DNA base stacking & Shape-complementary, blunt-ended dsDNA regions & Large-scale assembly [22, 73, 74]; reconfigurable devices [74] \\  & & information relay [77] \\  & & Rotary devices [78] \\ \hline Site-specific binding of target molecules & Incorporation of residues with specific chemical reactivity & Measurement devices [70, 85, 86, 107] \\  & Modified oligonucleotide aptamers & Drug delivery and nanorobotics [12, 90, 91, 92] \\ \hline Non-site-specific interactions with other molecules & Mixing DNA origami with crowding agents (e.g., poly(ethylene-glycol)), intercalators, or lipid bilayers & Measurement of molecular crowding [89] \\  & & Fine-tunable twisting motion [94] \\  & & Lipid-assisted diffusion [96, 97, 98] \\ \hline Light (UV/Vis) & Incorporation of photoresponsive molecules, e.g., azobenzenes & Photo-controllable assembly and disassembly of \\  & & nanostructures [104] \\  & & Photo-clavable and -controlled containers [100, 101] \\  & & Reconfigurable plasmonics [102] \\ \hline pH changes, Hoogsteen interactions & pH-sensitive DNA regions, e.g., i-motifs, G-quadruplex, or triple-forming sequences & Reconfigurable plasmonics [103, 105] \\  & & Assembly and disassembly of nanostructures [104] \\ \hline Temperature changes & Thermresponsive polymers & Thermresponsive actuation [106] \\ \hline Electric or magnetic fields & Polarizability of DNA in electric fields & Rotary devices, hinges, and levers [43, 111] \\  & Magnetic beads linked to origami & \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of the reviewed types of DNA origami motion.