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Dekai Zhou, Yuguang C Li, Pengtao Xu, Nicholas S McCool, Longqiu Li, Wei Wang, Thomas E Mallouk
Visible light driven Cu2O-Au micromotors exhibit rapid on/off switching and speed control. Electrochemical measurements confirm that the light-induced movement of the Cu2O-Au micromotors involves a self-electrophoresis mechanism modulated by the photoconductivity of Cu2O. This study extends the utilization of the electromagnetic spectrum for micro/nanomotors into the visible range.
December 2, 2016: Nanoscale
Fei Peng, Yingfeng Tu, Yongjun Men, Jan C M van Hest, Daniela A Wilson
With a convenient bottom-up approach, magnetic metallic nickel is grown in situ of a supramolecular nanomotor using the catalytic activities of preloaded platinum nanoparticles. After introducing magnetic segments, simultaneous guidance and steering of catalytically powered motors with additional magnetic fields are achieved. Guided motion in a tissue model is demonstrated.
November 28, 2016: Advanced Materials
Jiao Shi, Kun Cai, Qing-Hua Qin
A conceptual design is presented for a nanoengine governor based on the end interfacial effect of two rotary nanotubes. The governor contains a thermal-driven rotary nanomotor made from double-walled carbon nanotubes (DWCNTs) and a coaxially laid out rotary nanotube near one end of the nanomotor rotor. The rotation of the rotor in the nanomotor can be controlled by two features. One is the stator (the outer tube of DWCNTs) which has some end atoms with inward radial deviation (IRD) on the stator. The other is the relative rotation of the neighboring rotary tube of the rotor...
November 9, 2016: Nanotechnology
Deliang Yi, Qian Zhang, Yinghua Liu, Jiaying Song, Yi Tang, Frank Caruso, Yajun Wang
We report the synthesis of chemically asymmetric silica nanobottles (NBs) with a hydrophobic exterior surface (capped with 3-chloropropyl groups) and a hydrophilic interior surface for spatially selective cargo loading, and for application as nanoreactors and nanomotors. The silica NBs, which have a "flask bottle" shape with an average diameter of 350 nm and an opening of ca. 100 nm, are prepared by anisotropic sol-gel growth in a water/n-pentanol emulsion. Due to their chemically asymmetric properties, nanoparticles (NPs) with hydrophilic or hydrophobic surface properties can be selectively loaded inside the NBs or on the outside of the NBs, respectively...
November 14, 2016: Angewandte Chemie
Bumjin Jang, Wei Wang, Samuel Wiget, Andrew J Petruska, Xiangzhong Chen, Chengzhi Hu, Ayoung Hong, David Folio, Antoine Ferreira, Salvador Pané, Bradley J Nelson
We report the partial core-shell nanowire motors. These nanowires are fabricated using our previously developed electrodeposition-based technique, and their catalytic locomotion in the presence of H2O2 is investigated. Unlike conventional bimetallic nanowires that are self-electroosmotically propelled, our Au/Ru core-shell nanowires show both a noticeable decrease in rotational diffusivity and increase in motor speed with nanowire length. Numerical modelling based on self-electroosmosis attributes the decreases in rotational diffusivity to the formation of toroidal vortices at the nanowire tail, but fails to explain the speed increase with length...
October 18, 2016: ACS Nano
Baohu Dai, Jizhuang Wang, Ze Xiong, Xiaojun Zhan, Wei Dai, Chien-Cheng Li, Shien-Ping Feng, Jinyao Tang
Phototaxis is commonly observed in motile photosynthetic microorganisms. For example, green algae are capable of swimming towards a light source (positive phototaxis) to receive more energy for photosynthesis, or away from a light source (negative phototaxis) to avoid radiation damage or to hide from predators. Recently, with the aim of applying nanoscale machinery to biomedical applications, various inorganic nanomotors based on different propulsion mechanisms have been demonstrated. The only method to control the direction of motion of these self-propelled micro/nanomotors is to incorporate a ferromagnetic material into their structure and use an external magnetic field for steering...
October 17, 2016: Nature Nanotechnology
Fernando Soto, Gregory L Wagner, Victor Garcia-Gradilla, Kyle T Gillespie, Deepak R Lakshmipathy, Emil Karshalev, Chava Angell, Yi Chen, Joseph Wang
Herein we report a new design for acoustic nanoswimmers, making use of a nanoshell geometry that was synthesized using a sphere template process. Such shell-shaped nanomotors display highly efficient acoustic propulsion on the nanoscale by converting energy from the ambient acoustic field into motion. The propulsion mechanism of the nanoshell motors relies on acoustic streaming stress over the asymmetric surface to produce the driving force for motion. The shell-shaped nanomotors offer a high surface area to volume ratio, allow for efficient scalability and provide higher cargo towing capacity (in comparison to acoustically propelled nanowires)...
October 6, 2016: Nanoscale
Bahareh Kherzi, Martin Pumera
Self-propelled autonomous nano/micromotors are in the forefront of current materials science and technology research. These small machines convert chemical energy from the environment into propulsion, and they can move autonomously in the environment and are capable of chemotaxis or magnetotaxis. They can be used for drug delivery, microsurgeries or environmental remediation. It is of immense interest from a future biomedical application point of view to understand the motion of the nano/micromotors in microfluidic channels...
October 14, 2016: Nanoscale
Zhengyi Zhao, Hui Zhang, Dan Shu, Carlo Montemagno, Baoquan Ding, Jingyuan Li, Peixuan Guo
The significance of bionanomotors in nanotechnology is analogous to mechanical motors in daily life. Here the principle and approach for designing and constructing biomimetic nanomotors with continuous single-directional motion are reported. This bionanomotor is composed of a dodecameric protein channel, a six-pRNA ring, and an ATPase hexamer. Based on recent elucidations of the one-way revolving mechanisms of the phi29 double-stranded DNA (dsDNA) motor, various RNA and protein elements are designed and tested by single-molecule imaging and biochemical assays, with which the motor with active components has been constructed...
October 6, 2016: Small
Shang Yik Reigh, Mu-Jie Huang, Jeremy Schofield, Raymond Kapral
Active media, whose constituents are able to move autonomously, display novel features that differ from those of equilibrium systems. In addition to naturally occurring active systems such as populations of swimming bacteria, active systems of synthetic self-propelled nanomotors have been developed. These synthetic systems are interesting because of their potential applications in a variety of fields. Janus particles, synthetic motors of spherical geometry with one hemisphere that catalyses the conversion of fuel to product and one non-catalytic hemisphere, can propel themselves in solution by self-diffusiophoresis...
November 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Gerald S Manning
The dynamic process underlying muscle contraction is the parallel sliding of thin actin filaments along an immobile thick myosin fiber powered by oar-like movements of protruding myosin cross bridges (myosin heads). The free energy for functioning of the myosin nanomotor comes from the hydrolysis of ATP bound to the myosin heads. The unit step of translational movement is based on a mechanical-chemical cycle involving ATP binding to myosin, hydrolysis of the bound ATP with ultimate release of the hydrolysis products, stress-generating conformational changes in the myosin cross bridge, and relief of built-up stress in the myosin power stroke...
December 2016: Biopolymers
Daniel Hoersch
The F1 sub-complex of ATP synthase is a biological nanomotor that converts the free energy of ATP hydrolysis into mechanical work with an astonishing efficiency of up to 100% (Kinosita et al., 2000). To probe the principal mechanics of the machine, I re-engineered the active site of E.coli F1 ATPase with a structure-based protein design approach: by incorporation of a site-specific, photoswitchable crosslinker, whose end-to-end distance can be modulated by illumination with light of two different wavelengths, a dynamic constraint was imposed on the inter-atomic distances of the α and β subunits...
2016: PeerJ
Jessica Richard, Elizabeth D Kim, Hoang Nguyen, Catherine D Kim, Sunyoung Kim
How signals between the kinesin active and cytoskeletal binding sites are transmitted is an open question and an allosteric question. By extracting correlated evolutionary changes within 700+ sequences, we built a model of residues that are energetically coupled and that define molecular routes for signal transmission. Typically, these coupled residues are located at multiple distal sites and thus are predicted to form a complex, non-linear network that wires together different functional sites in the protein...
September 30, 2016: Journal of Biological Chemistry
Xu Zhou, Chuang Li, Yu Shao, Chun Chen, Zhongqiang Yang, Dongsheng Liu
By integrating a DNA motor based on an i-motif sequence that undergoes a pH-dependent conformational transition into a DNA hydrogel network, such microscopic transition leads to a macroscopic change in mechanical properties. This strategy allows reversible tuning of the mechanical strength of the hydrogel ranging from 250 Pa to 1000 Pa.
August 23, 2016: Chemical Communications: Chem Comm
Wei Zhe Teo, Martin Pumera
As we progress towards employing self-propelled micro-/nanomotors in envisioned applications such as cargo delivery, environmental remediation, and therapeutic treatments, precise control of the micro-/nanomotors direction and their speed is essential. In this Review, major emerging approaches utilized for the motion control of micro-/nanomotors have been discussed, together with the lastest publications describing these approaches. Future studies could incorporate investigations on micro-/nanomotors motion control in a real-world environment in which matrix complexity might disrupt successful manipulation of these small-scale devices...
October 10, 2016: Chemistry: a European Journal
Kun Cai, Jingzhou Yu, Lingnan Liu, Jiao Shi, Qing H Qin
Due to the extremely small dimensions and super high frequency of the rotor in a thermally driven rotary nanomotor made from carbon nanostructures, measuring the rotational frequency of the nanomotor is still an open issue. To this end, a measuring system is constructed in which a spring wing is connected with the rotor to provide collisions with a probe tip whose deflection reflects the rotational frequency of the rotor. The spring wing is formed by connecting an end-tube from a carbon nanotube and a graphene with differently hydrogenated surfaces...
August 10, 2016: Physical Chemistry Chemical Physics: PCCP
Peng Jing, Benjamin Burris, Rong Zhang
In the Phi29 bacteriophage, the DNA packaging nanomotor packs its double-stranded DNA genome into the virus capsid. At the late stage of DNA packaging, the negatively charged genome is increasingly compacted at a higher density in the capsid with a higher internal pressure. During the process, two Donnan effects, osmotic pressure and Donnan equilibrium potentials, are significantly amplified, which, in turn, affect the channel activity of the portal protein, GP10, embedded in the semipermeable capsid shell...
July 12, 2016: Biophysical Journal
Flory Wong, Ayusman Sen
We have developed a highly efficient, bubble-free autonomous nanomotor based on a nanobattery. Bimetallic silver-platinum nanorods are powered by self-electrophoresis and show speeds much higher than those of other electrophoretic motors at similar fuel concentrations. The fuel (I2) can be regenerated by exposure to ambient light, leading to renewed motion of the motor. This versatile system can also be made into a micropump that transports fluid and particles.
July 26, 2016: ACS Nano
Meihan Liu, Juan Cheng, Shern Ren Tee, Sarangapani Sreelatha, Iong Ying Loh, Zhisong Wang
Replicating efficient chemical energy utilization of biological nanomotors is one ultimate goal of nanotechnology and energy technology. Here, we report a rationally designed autonomous bipedal nanowalker made of DNA that achieves a fuel efficiency of less than two fuel molecules decomposed per productive forward step, hence breaking a general threshold for chemically powered machines invented to date. As a genuine enzymatic nanomotor without changing itself nor the track, the walker demonstrates a sustained motion on an extended double-stranded track at a speed comparable to previous burn-bridge motors...
June 28, 2016: ACS Nano
Jingxin Shao, Mingjun Xuan, Qiang He, Luru Dai
The rapid emergence of nanotechnology and biotechnology provides revolutionary developments for drug delivery system. Recently, drug delivery has been attracted extensive research interest; great efforts have been contributed to improve the functions of these carriers and their applications. Active drug delivery is currently approved as an ideal approach for targeted transportation in the biological entity, and can cooperate with therapeutic mediums and transporting cargoes. In this review, several active targeted cargo mediated drug delivery patterns have been summarized including molecular motor, bio-camouflaged particles, and self-propelled nanomotors...
June 2, 2016: Current Drug Targets
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