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Peter H Colberg, Raymond Kapral
The collective behavior of chemically propelled sphere-dimer motors made from linked catalytic and noncatalytic spheres in a quasi-two-dimensional confined geometry is studied using a coarse-grained microscopic dynamical model. Chemical reactions at the catalytic spheres that convert fuel to product generate forces that couple to solvent degrees of freedom as a consequence of momentum conservation in the microscopic dynamics. The collective behavior of the many-body system is influenced by direct intermolecular interactions among the motors, chemotactic effects due to chemical gradients, hydrodynamic coupling, and thermal noise...
August 14, 2017: Journal of Chemical Physics
Yunru Yu, Luoran Shang, Wei Gao, Ze Zhao, Huan Wang, Yuanjin Zhao
Attracted by the biomachines of nature, considerable efforts have been devoted to developing artificial micro/nanomotors, which are helpful in diverse potential biomedical and environmental areas. Here, we present a novel flow lithography integrated microfluidic spinning and spiraling system for the continuous and controllable generation of bioinspired helical micromotors. Benefit from the fast online gelation and polymerization, the resultant helical micromotors could be imparted with Janus, triplex, and core-shell cross-sectional structures that have never been achieved by other methods...
July 29, 2017: Angewandte Chemie
Ognjen Ilic, Ido Kaminer, Bo Zhen, Owen D Miller, Hrvoje Buljan, Marin Soljačić
Shaping the topology of light, by way of spin or orbital angular momentum engineering, is a powerful tool to manipulate matter on the nanoscale. Conventionally, such methods focus on shaping the incident beam of light and not the full interaction between the light and the object to be manipulated. We theoretically show that tailoring the topology of the phase space of the light particle interaction is a fundamentally more versatile approach, enabling dynamics that may not be achievable by shaping of the light alone...
June 2017: Science Advances
Qianlan Rao, Tieyan Si, Zhiguang Wu, Mingjun Xuan, Qiang He
Self-propelled micro/nanomotors possess tremendous exciting promise in diverse fields. We describe an asymmetric, fuel-free and near-infrared light-powered torpedo micromotor, which is constructed by using a porous membrane-assisted layer-by-layer sol-gel method to form silica multilayer inside the pores, following by the deposition of gold nanoparticles on one end of the pores. In the absence of chemical fuels, the high propulsion of microtorpedoes under illumination of near-infrared light is owing to the photo-thermal effect of gold clusters, generating a thermal gradient inside the microtorpedoes...
July 4, 2017: Scientific Reports
José García-Torres, Albert Serrà, Pietro Tierno, Xavier Alcobé, Elisa Vallés
Electrochemically fabricated magnetic mesoporous CoNi@Pt nanorods are excellent nanomotors with controlled magnetic propulsion and excellent catalytic properties. The core-shell structure allows a double functionality: (i) controlled motion of the nanorods by applying rotating magnetic fields at different frequencies and field strengths and (ii) effective catalytic activity of the platinum shell for reactions involving sodium borohydride. The structure and magnetic properties of the CoNi core are not modified by the presence of the Pt shell...
July 19, 2017: ACS Applied Materials & Interfaces
Sheng Wang, Zhenzhen Jiang, Shenshen Ouyang, Zhipeng Dai, Tao Wang
We describe a highly effective bubble-propelled nanomotor for the photocatalytic decomposition of organic pollutants in water. Two different tubular TiO2 nanomotor systems are presented: one with Pt nanoparticles decorated on the inner surface and the other with Pt nanoparticles decorated on the outer surface. This is the first time that we have observed the autonomous movement of a tubular nanomotor without the aid of any surfactant, as well as a tubular nanomotor externally decorated with Pt propelled by oxygen bubbles...
July 19, 2017: ACS Applied Materials & Interfaces
Jia Zhuang, Allison P Young, Chia-Kuang Tsung
Owing to the progressive development of metal-organic-frameworks (MOFs) synthetic processes and considerable potential applications in last decade, integrating biomolecules into MOFs has recently gain considerable attention. Biomolecules, including lipids, oligopeptides, nucleic acids, and proteins have been readily incorporated into MOF systems via versatile formulation methods. The formed biomolecule-MOF hybrid structures have shown promising prospects in various fields, such as antitumor treatment, gene delivery, biomolecular sensing, and nanomotor device...
June 22, 2017: Small
Jizhuang Wang, Ze Xiong, Xiaojun Zhan, Baohu Dai, Jing Zheng, Jun Liu, Jinyao Tang
Over the last decades, scientists have endeavored to develop nanoscopic machines and envisioned that these tiny machines could be exploited in biomedical applications and novel material fabrication. Here, a visible-/near-infrared light-driven nanomotor based on a single silicon nanowire is reported. The silicon nanomotor harvests energy from light and propels itself by the self-electrophoresis mechanism. Due to the high efficiency, the silicon nanowire can be readily driven by visible and near-infrared illumination at ultralow light intensity (≈3 mW cm(-2) )...
August 2017: Advanced Materials
Xiankun Lin, Tieyan Si, Zhiguang Wu, Qiang He
As artificial active colloids, micro-/nanomotors (MNMs) can convert energy from the environment into mechanical motion in different fluids, showing potential applications in diverse fields such as targeted drug delivery and photothermal therapy. However, chemical fuels for typical catalytic MNMs, e.g., hydrogen peroxide, are highly toxic to organisms, and thus fuel-free MNMs are required. Recently, we have developed near-infrared light (NIR) propelled MNMs through integrating plasmonic gold nanoshells into nanoparticles or layer-by-layer assemblies in an asymmetric manner...
May 22, 2017: Physical Chemistry Chemical Physics: PCCP
Fei Peng, Yingfeng Tu, Daniela A Wilson
Inspired by highly efficient natural motors, synthetic micro/nanomotors are self-propelled machines capable of converting the supplied fuel into mechanical motion. A significant advance has been made in the construction of diverse motors over the last decade. These synthetic motor systems, with rapid transporting and efficient cargo towing abilities, are expected to open up new horizons for various applications. Utilizing emergent motor platforms for in vivo applications is one important aspect receiving growing interest as conventional therapeutic methodology still remains limited for cancer, heart, or vasculature diseases...
May 19, 2017: Chemical Society Reviews
Yingfeng Tu, Fei Peng, Paul B White, Daniela A Wilson
The development of artificial nanomotor systems that are stimuli-responsive is still posing many challenges. Herein, we demonstrate the self-assembly of a redox-responsive stomatocyte nanomotor system, which can be used for triggered drug release under biological reducing conditions. The redox sensitivity was introduced by incorporating a disulfide bridge between the hydrophilic poly(ethylene glycol) block and the hydrophobic polystyrene block. When incubated with the endogenous reducing agent glutathione at a concentration comparable to that within cells, the external PEG shells of these stimuli-responsive nanomotors are cleaved...
June 19, 2017: Angewandte Chemie
Likui Yang, Kun Cai, Jiao Shi, Qing H Qin
Many factors can have a significant influence on the output power of a thermally driven rotary nanomotor made of carbon nanotubes (CNTs). Making use of a computational molecular dynamics approach, we evaluate for the first time the output power of a nanomotor, considering some of the main factors including temperature, the diameter of the rotor and the number of IRD atoms (N) on the stator. When applying extra-resistant torque to the rotor to let the stable value of the rotational frequency of the rotor fluctuate near zero, the value of the resistant torque can be considered as the output power of the rotor...
May 26, 2017: Nanotechnology
Berta Esteban-Fernández de Ávila, Doris E Ramírez-Herrera, Susana Campuzano, Pavimol Angsantikul, Liangfang Zhang, Joseph Wang
Direct and efficient intracellular delivery of enzymes to cytosol holds tremendous therapeutic potential while remaining an unmet technical challenge. Herein, an ultrasound (US)-propelled nanomotor approach and a high-pH-responsive delivery strategy are reported to overcome this challenge using caspase-3 (CASP-3) as a model enzyme. Consisting of a gold nanowire (AuNW) motor with a pH-responsive polymer coating, in which the CASP-3 is loaded, the resulting nanomotor protects the enzyme from release and deactivation prior to reaching an intracellular environment...
June 27, 2017: ACS Nano
Laurens Deprez, Pierre de Buyl
Chemotaxis is the response of a particle to a gradient in the chemical composition of the environment. While it was originally observed for biological organisms, it is of great interest in the context of synthetic active particles such as nanomotors. Experimental demonstration of chemotaxis for chemically-powered colloidal nanomotors was reported in the literature in the context of chemo-attraction in a still fluid or in a microfluidic channel where the gradient is sustained by a specific inlet geometry. In this work, we use mesoscopic particle-based simulations of the colloid and solvent to demonstrate chemotaxis in a microfluidic channel...
April 26, 2017: Soft Matter
Yingfeng Tu, Fei Peng, Xiaofeng Sui, Yongjun Men, Paul B White, Jan C M van Hest, Daniela A Wilson
Self-propelled catalytic micro- and nanomotors have been the subject of intense study over the past few years, but it remains a continuing challenge to build in an effective speed-regulation mechanism. Movement of these motors is generally fully dependent on the concentration of accessible fuel, with propulsive movement only ceasing when the fuel consumption is complete. Here we report a demonstration of control over the movement of self-assembled stomatocyte nanomotors via a molecularly built, stimulus-responsive regulatory mechanism...
May 2017: Nature Chemistry
K E Dunn, M C Leake, A J M Wollman, M A Trefzer, S Johnson, A M Tyrrell
DNA has been used to construct a wide variety of nanoscale molecular devices. Inspiration for such synthetic molecular machines is frequently drawn from protein motors, which are naturally occurring and ubiquitous. However, despite the fact that rotary motors such as ATP synthase and the bacterial flagellar motor play extremely important roles in nature, very few rotary devices have been constructed using DNA. This paper describes an experimental study of the putative mechanism of a rotary DNA nanomotor, which is based on strand displacement, the phenomenon that powers many synthetic linear DNA motors...
March 2017: Royal Society Open Science
Kun Cai, Jingzhou Yu, Jiao Shi, Qing-Hua Qin
In the fabrication of a thermally driven rotary nanomotor with the dimension of a few nanometers, fabrication and control precision may have great influence on rotor's stability of rotational frequency (SRF). To investigate effects of uncertainty of some major factors including temperature, tube length, axial distance between tubes, diameter of tubes and the inward radial deviation (IRD) of atoms in stators on the frequency's stability, theoretical analysis integrating with numerical experiments are carried out...
April 10, 2017: Scientific Reports
Md Mushfiqur Rahman, Mokter Mahmud Chowdhury, Md Kawsar Alam
Using molecular dynamics simulations, it is shown that a carbon nanotube (CNT) suspended in water and subjected to a rotating electric field of proper magnitude and angular speed can be rotated with the aid of water dipole orientations. Based on this principle, a rotational nanomotor structure is designed and the system is simulated in water. Use of the fast responsiveness of electric-field-induced CNT orientation in water is employed and its operation at ultrahigh-speed (over 10(11) r.p.m.) is shown. To explain the basic mechanism, the behavior of the rotational actuation, originated from the water dipole orientation, is also analyzed ...
May 2017: Small
Jacek Czub, Miłosz Wieczór, Bartosz Prokopowicz, Helmut Grubmüller
F1-ATPase is a highly efficient molecular motor that can synthesize ATP driven by a mechanical torque. Its ability to function reversibly in either direction requires tight mechanochemical coupling between the catalytic domain and the rotating central shaft, as well as temporal control of substrate binding and product release. Despite great efforts and significant progress, the molecular details of this synchronized and fine-tuned energy conversion mechanism are not fully understood. Here, we use extensive molecular dynamics simulations to reconcile recent single-molecule experiments with structural data and provide a consistent thermodynamic, kinetic and mechanistic description of the main rotary substep in the synthetic cycle of mammalian ATP synthase...
March 9, 2017: Journal of the American Chemical Society
Carla Schmidt, Jamie A Macpherson, Andy M Lau, Ken Wei Tan, Franca Fraternali, Argyris Politis
Mass spectrometry (MS) has become an indispensable tool for investigating the architectures and dynamics of macromolecular assemblies. Here we show that covalent labeling of solvent accessible residues followed by their MS-based identification yields modeling restraints that allow mapping the location and orientation of subunits within protein assemblies. Together with complementary restraints derived from cross-linking and native MS, we built native-like models of four heterocomplexes with known subunit structures and compared them with available X-ray crystal structures...
February 7, 2017: Analytical Chemistry
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