Optically Resolving the Dynamic Walking of a Plasmonic Walker Couple

Abstract

Deterministic placement and dynamic manipulation of individual plasmonic nanoparticles with nanoscale precision feature an important step toward active nanoplasmonic devices with prescribed levels of performance and functionalities at optical frequencies. In this Letter, we demonstrate a plasmonic walker couple system, in which two gold nanorod walkers can independently or simultaneously perform stepwise walking powered by DNA hybridization along the same DNA origami track. We utilize optical spectroscopy to resolve such dynamic walking with nanoscale steps well below the optical diffraction limit. We also show that the number of walkers and the optical response of the system can be correlated. Our studies exemplify the power of plasmonics, when integrated with DNA nanotechnology for realization of advanced artificial nanomachinery with tailored optical functionalities.

Chiral plasmonics

“…The same group of authors extended the concept by incorporating a total of three rods. They showed not only that the optical response could be fully controlled with the help of an external stimulus but also that it is also possible to optically resolve the movements of two separate and individually addressable walkers on the DNA origami ( 78 ). …”

Synthesis and Applications of Stimuli‐Responsive DNA‐Based Nano‐ and Micro‐Sized Capsules

“…The rich toolbox of triggers to reconfigure DNA nanostructures provided broad means to construct and operate DNA switches, [13] DNA machines, [41,42] logic gates, and computing circuitries, [65,69] and to activate enzyme [162,178] or DNAzyme [179] cascades. Besides the use of DNA to assemble ingenious macromolecular supramolecular systems such as interlocked stimuli-responsive dynamicallycontrolled DNA catenane or rotaxane nanostructures, [180] or the use of DNA scaffolds for the programmed deposition of plasmonic nanoparticles revealing switchable chiroplasmonic properties [76,181] or optical plasmonic antenna functions, [164] new stimuli-responsive DNA-based materials were developed. Besides the use of DNA to assemble ingenious macromolecular supramolecular systems such as interlocked stimuli-responsive dynamicallycontrolled DNA catenane or rotaxane nanostructures, [180] or the use of DNA scaffolds for the programmed deposition of plasmonic nanoparticles revealing switchable chiroplasmonic properties [76,181] or optical plasmonic antenna functions, [164] new stimuli-responsive DNA-based materials were developed.…”

“…For example, disulfide bridges were reported to stabilize DNA duplex structures, while the reduction of the disulfide by thiols led to the separation of the duplex structures. [74][75][76][77] The development of gated, stimuli-responsive, micro-, or nano-sized drug carriers attracted substantial research efforts in the past two decades, [78,79] and different triggers, such as pH, [80][81][82] thermal, [83] light, [84,85] redox stimuli, [86,87] chemical, [88] or enzymatic [89][90][91] triggers have been used to unlock micro-sized drug carriers. [27][28][29][30] Photoisomerization of the trans-azobenzene units to the cis-azobenzene configuration, which lacks affinity toward the duplex DNA, results in the release of the photoactive units, in the weakening of the duplex structures, and eventually in their separation.…”

“…The reconfiguration principles were used to selectively cleave or isomerize DNA-origami oligomers, [57] to stimulate reversible hydrogel-to-solution transitions, [58][59][60] to switch catalytic cascades of enzymes, [61] and to switch the catalytic functions of DNAzymes. [74][75][76][77] The development of gated, stimuli-responsive, micro-, or nano-sized drug carriers attracted substantial research efforts in the past two decades, [78,79] and different triggers, such as pH, [80][81][82] thermal, [83] light, [84,85] redox stimuli, [86,87] chemical, [88] or enzymatic [89][90][91] triggers have been used to unlock micro-sized drug carriers. [74][75][76][77] The development of gated, stimuli-responsive, micro-, or nano-sized drug carriers attracted substantial research efforts in the past two decades, [78,79] and different triggers, such as pH, [80][81][82] thermal, [83] light, [84,85] redox stimuli, [86,87] chemical, [88] or enzymatic [89][90][91] triggers have been used to unlock micro-sized drug carriers.…”

“…[62] Different applications of reconfigurable nucleic acid structures and DNA switches were demonstrated, including their use as sensors, [63,64] the operation of logic gates and computing circuits, [65][66][67][68][69] the design of switchable DNA hydrogels exhibiting shape memory [70][71][72] or triggered mechanical functions, [73] and the triggered organization of metallic nanoparticles that reveal unique plasmonic properties. [74][75][76][77] The development of gated, stimuli-responsive, micro-, or nano-sized drug carriers attracted substantial research efforts in the past two decades, [78,79] and different triggers, such as pH, [80][81][82] thermal, [83] light, [84,85] redox stimuli, [86,87] chemical, [88] or enzymatic [89][90][91] triggers have been used to unlock micro-sized drug carriers. The reconfigurable properties of DNA and the response of DNA structures to pH, heat, potential biomarkers, e.g., ATP, VEGF, or microRNAs, and the ability to target cancer cells by sequence-specific aptamers, e.g., AS1411, [92,93] provide versatile means to tailor stimuli-responsive micro-or nanocarriers consisting of nucleic acid/carrier hybrids.…”